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Barksdale BR, Doss MK, Fonzo GA, Nemeroff CB. The mechanistic divide in psychedelic neuroscience: An unbridgeable gap? Neurotherapeutics 2024; 21:e00322. [PMID: 38278658 DOI: 10.1016/j.neurot.2024.e00322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/10/2024] [Accepted: 01/10/2024] [Indexed: 01/28/2024] Open
Abstract
In recent years, psychedelics have generated considerable excitement and interest as potential novel therapeutics for an array of conditions, with the most advanced evidence base in the treatment of certain severe and/or treatment-resistant psychiatric disorders. An array of clinical and pre-clinical evidence has informed our current understanding of how psychedelics produce profound alterations in consciousness. Mechanisms of psychedelic action include receptor binding and downstream cellular and transcriptional pathways, with long-term impacts on brain structure and function-from the level of single neurons to large-scale circuits. In this perspective, we first briefly review and synthesize separate lines of research on potential mechanistic processes underlying the acute and long-term effects of psychedelic compounds, with a particular emphasis on highlighting current theoretical models of psychedelic drug action and their relationships to therapeutic benefits for psychiatric and brain-based disorders. We then highlight an existing area of ongoing controversy we argue is directly informed by theoretical models originating from disparate levels of inquiry, and we ultimately converge on the notion that bridging the current chasm in explanatory models of psychedelic drug action across levels of inquiry (molecular, cellular, circuit, and psychological/behavioral) through innovative methods and collaborative efforts will ultimately yield the comprehensive understanding needed to fully capitalize on the potential therapeutic properties of these compounds.
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Affiliation(s)
- Bryan R Barksdale
- Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School, Austin, TX, USA
| | - Manoj K Doss
- Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School, Austin, TX, USA
| | - Gregory A Fonzo
- Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School, Austin, TX, USA
| | - Charles B Nemeroff
- Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School, Austin, TX, USA.
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2
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Tabaac BJ, Shinozuka K, Arenas A, Beutler BD, Cherian K, Evans VD, Fasano C, Muir OS. Psychedelic Therapy: A Primer for Primary Care Clinicians-Historical Perspective and Overview. Am J Ther 2024; 31:e97-e103. [PMID: 38518266 DOI: 10.1097/mjt.0000000000001727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2024]
Abstract
BACKGROUND Psychedelic drugs have recently emerged as plausibly effective pharmacological agents for the management of depression, anxiety, and other neuropsychiatric conditions, including those that are treatment-resistent. The latter half of the 20th century marked a revolution in the treatment of mental illnesses, exemplified by the introduction of selective serotonin reuptake inhibitors and other pharmacological agents. Nevertheless, mental illness remains a major public health crisis, affecting nearly one billion individuals worldwide. AREAS OF UNCERTAINTY Because of the decades-long status of several psychedelics as Schedule I drugs, there have not been very many large, double-blind, randomized controlled trials of psychedelics. Owing to small sample sizes, there may be rare yet serious adverse events that have not been reported in the clinical trials thus far. THERAPEUTIC ADVANCES Esketamine, a dissociative hallucinogen drug, was approved for the management of major depressive disorder by the Food and Drug Administration in 2019. As of January 2024, two Phase III trials of 3,4-methylenedioxymethamphetamine (MDMA), a synthetic drug that inhibits the serotonin transporter, have been completed; the results indicate that MDMA is superior to existing pharmacological treatments for post-traumatic stress disorder. A phase III trial of psilocybin, a naturally occurring serotonin receptor partial agonist, is currently underway. The following series details the current state of research in psychedelic therapeutics, including lysergic acid diethylamide (LSD), N-N-dimethyltryptamine (DMT) and ayahuasca, psilocybin, ibogaine, MDMA, and ketamine. LIMITATIONS While initial clinical trials of psychedelics for depression were very promising, trials of psilocybin with larger sample sizes (100+ participants) suggest that its remission rate is 25%-29%. This is about the same as the remission rate of antidepressants, which is roughly 30% according to the landmark STAR*D trial. CONCLUSIONS Psychedelic drugs and structural derivatives offer a great deal of promise for the management of a wide range of psychiatric morbidities. It is imperative that clinicians become familiar with these novel agents and learn how to integrate psychedelic therapy with the rest of their care through open communication and referral.
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Affiliation(s)
- Burton J Tabaac
- University of Nevada, Reno School of Medicine, Reno, NV
- Department of Neurology, Carson Tahoe Health, Carson City, NV
| | - Kenneth Shinozuka
- Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, United Kingdom
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Alejandro Arenas
- Department of Anesthesiology, University of Washington School of Medicine, Seattle, WA
| | - Bryce D Beutler
- University of Southern California, Keck School of Medicine, Los Angeles, CA
| | - Kirsten Cherian
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA
| | - Viviana D Evans
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY
| | | | - Owen S Muir
- Fermata Health, Brooklyn, NY; and
- Acacia Clinics, Sunnyvale, CA
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3
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Frautschi PC, Singh AP, Stowe NA, Yu JPJ. Multimodal Neuroimaging of the Effect of Serotonergic Psychedelics on the Brain. AJNR Am J Neuroradiol 2024:ajnr.A8118. [PMID: 38360790 DOI: 10.3174/ajnr.a8118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 11/20/2023] [Indexed: 02/17/2024]
Abstract
The neurobiological mechanisms underpinning psychiatric disorders such as treatment-resistant major depression, post-traumatic stress disorder, and substance use disorders, remain unknown. Psychedelic compounds, such as psilocybin, lysergic acid diethylamide, and N,N-dimethyltryptamine, have emerged as potential therapies for these disorders because of their hypothesized ability to induce neuroplastic effects and alter functional networks in the brain. Yet, the mechanisms underpinning the neurobiological treatment response remain obscure. Quantitative neuroimaging is uniquely positioned to provide insight into the neurobiological mechanisms of these emerging therapies and quantify the patient treatment response. This review aims to synthesize our current state-of-the-art understanding of the functional changes occurring in the brain following psilocybin, lysergic acid diethylamide, or N,N-dimethyltryptamine administration in human participants with fMRI and PET. We further aim to disseminate our understanding of psychedelic compounds as they relate to neuroimaging with the goal of improved diagnostics and treatment of neuropsychiatric illness.
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Affiliation(s)
- Paloma C Frautschi
- Department of Radiology (P.C.F., A.P.S., J.-P.J.Y.), University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Ajay P Singh
- Department of Radiology (P.C.F., A.P.S., J.-P.J.Y.), University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
- Graduate Program in Cellular and Molecular Biology (A.P.S., J.-P.J.Y.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Nicholas A Stowe
- Neuroscience Training Program, Wisconsin Institutes for Medical Research (N.A.S., J.-P.J.Y.), University of Wisconsin-Madison, Madison, Wisconsin
| | - John-Paul J Yu
- Department of Radiology (P.C.F., A.P.S., J.-P.J.Y.), University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
- Neuroscience Training Program, Wisconsin Institutes for Medical Research (N.A.S., J.-P.J.Y.), University of Wisconsin-Madison, Madison, Wisconsin
- Graduate Program in Cellular and Molecular Biology (A.P.S., J.-P.J.Y.), University of Wisconsin-Madison, Madison, Wisconsin
- Department of Biomedical Engineering (J.-P.J.Y.), University of Wisconsin-Madison, Madison, Wisconsin
- Department of Psychiatry (J.-P.J.Y.), University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
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Hatzipantelis CJ, Olson DE. The Effects of Psychedelics on Neuronal Physiology. Annu Rev Physiol 2024; 86:27-47. [PMID: 37931171 PMCID: PMC10922499 DOI: 10.1146/annurev-physiol-042022-020923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Psychedelics are quite unique among drugs that impact the central nervous system, as a single administration of a psychedelic can both rapidly alter subjective experience in profound ways and produce sustained effects on circuits relevant to mood, fear, reward, and cognitive flexibility. These remarkable properties are a direct result of psychedelics interacting with several key neuroreceptors distributed across the brain. Stimulation of these receptors activates a variety of signaling cascades that ultimately culminate in changes in neuronal structure and function. Here, we describe the effects of psychedelics on neuronal physiology, highlighting their acute effects on serotonergic and glutamatergic neurotransmission as well as their long-lasting effects on structural and functional neuroplasticity in the cortex. We propose that the neurobiological changes leading to the acute and sustained effects of psychedelics might be distinct, which could provide opportunities for engineering compounds with optimized safety and efficacy profiles.
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Affiliation(s)
- Cassandra J Hatzipantelis
- Institute for Psychedelics and Neurotherapeutics, University of California, Davis, Davis, California, USA;
- Department of Chemistry, University of California, Davis, Davis, California, USA
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, California, USA
| | - David E Olson
- Institute for Psychedelics and Neurotherapeutics, University of California, Davis, Davis, California, USA;
- Department of Chemistry, University of California, Davis, Davis, California, USA
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, California, USA
- Center for Neuroscience, University of California, Davis, Davis, California, USA
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Stoliker D, Novelli L, Vollenweider FX, Egan GF, Preller KH, Razi A. Neural Mechanisms of Resting-State Networks and the Amygdala Underlying the Cognitive and Emotional Effects of Psilocybin. Biol Psychiatry 2024:S0006-3223(24)00004-0. [PMID: 38185235 DOI: 10.1016/j.biopsych.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 12/19/2023] [Accepted: 01/02/2024] [Indexed: 01/09/2024]
Abstract
BACKGROUND Serotonergic psychedelics, such as psilocybin, alter perceptual and cognitive systems that are functionally integrated with the amygdala. These changes can alter cognition and emotions that are hypothesized to contribute to their therapeutic utility. However, the neural mechanisms of cognitive and subcortical systems altered by psychedelics are not well understood. METHODS We used resting-state functional magnetic resonance images collected during a randomized, double-blind, placebo-controlled clinical trial of 24 healthy adults under 0.2 mg/kg psilocybin to estimate the directed (i.e., effective) changes between the amygdala and 3 large-scale resting-state networks involved in cognition. These networks are the default mode network, the salience network, and the central executive network. RESULTS We found a pattern of decreased top-down effective connectivity from these resting-state networks to the amygdala. Effective connectivity decreased within the default mode network and salience network but increased within the central executive network. These changes in effective connectivity were statistically associated with behavioral measures of altered cognition and emotion under the influence of psilocybin. CONCLUSIONS Our findings suggest that temporary amygdala signal attenuation is associated with mechanistic changes to resting-state network connectivity. These changes are significant for altered cognition and perception and suggest targets for research investigating the efficacy of psychedelic therapy for internalizing psychiatric disorders. More broadly, our study suggests the value of quantifying the brain's hierarchical organization using effective connectivity to identify important mechanisms for basic cognitive function and how they are integrated to give rise to subjective experiences.
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Affiliation(s)
- Devon Stoliker
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia; Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia
| | - Leonardo Novelli
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia; Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia
| | - Franz X Vollenweider
- Department of Psychiatry, Psychotherapy & Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Gary F Egan
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia; Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia
| | - Katrin H Preller
- Department of Psychiatry, Psychotherapy & Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Adeel Razi
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia; Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia; Wellcome Centre for Human Neuroimaging, University College London, London, United Kingdom; CIFAR Azrieli Global Scholars Program, CIFAR, Toronto, Ontario, Canada.
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6
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Maćkowiak M. Psychedelics action and schizophrenia. Pharmacol Rep 2023; 75:1350-1361. [PMID: 37899392 PMCID: PMC10661800 DOI: 10.1007/s43440-023-00546-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/09/2023] [Accepted: 10/16/2023] [Indexed: 10/31/2023]
Abstract
Psychedelics are compounds acting by serotonin 5-hydroxytryptamine (5-HT)2A receptor activation and induce several behavioral responses. They are of special interest because of their positive effects on neuropsychiatric disorders (depression and posttraumatic stress disorder). However, several findings revealed that some psychedelic actions are similar to symptoms observed in schizophrenia (psychosis, sensorimotor gating impairments, attention, and working memory deficits) which might limit their clinical applications. Psychedelics activate some neurotransmitters, i.e., serotonergic, and glutamatergic, that are also impaired in schizophrenia. Therefore, the neurobiological background of psychedelics and schizophrenia is partially similar. Another important aspect to discuss is the perspective of using psychedelics in schizophrenia therapy. Postmortem studies showed a loss of synapses in schizophrenia, and the positive effects of psychedelics on neuroplasticity (synaptogenesis, neurogenesis, and neuritogenesis) might be essential in the context of schizophrenia therapy. However, because of psychedelics' psychotic action, the recommended doses of psychedelics in schizophrenia treatment are not established, and subpsychedelic dosing or microdosing are considered. Exploratory studies are needed to determine the tolerability of treatment and appropriate dosing regimen. Another therapeutic option is using non-hallucinogenic psychedelic analogs that also induce neuroplastic outcomes but do not have psychotogenic effects. Further preclinical and clinical studies are needed to recognize the potential effectiveness of 5-HT2A agonists in schizophrenia therapy.
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Affiliation(s)
- Marzena Maćkowiak
- Laboratory of Pharmacology and Brain Biostructure, Pharmacology Department, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
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Gattuso JJ, Wilson C, Hannan AJ, Renoir T. Psilocybin as a lead candidate molecule in preclinical therapeutic studies of psychiatric disorders: A systematic review. J Neurochem 2023. [PMID: 38019032 DOI: 10.1111/jnc.16017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 11/02/2023] [Accepted: 11/10/2023] [Indexed: 11/30/2023]
Abstract
Psilocybin is the main psychoactive compound found in hallucinogenic/magic mushrooms and can bind to both serotonergic and tropomyosin receptor kinase b (TrkB) receptors. Psilocybin has begun to show efficacy for a range of neuropsychiatric conditions, including treatment-resistant depression and anxiety disorders; however, neurobiological mechanisms are still being elucidated. Clinical research has found that psilocybin can alter functional connectivity patterns in human brains, which is often associated with therapeutic outcomes. However, preclinical research affords the opportunity to assess the potential cellular mechanisms by which psilocybin may exert its therapeutic effects. Preclinical rodent models can also facilitate a more tightly controlled experimental context and minimise placebo effects. Furthermore, where there is a rationale, preclinical researchers can investigate psilocybin administration in neuropsychiatric conditions that have not yet been researched clinically. As a result, we have systematically reviewed the knowledge base, identifying 82 preclinical studies which were screened based on specific criteria. This resulted in the exclusion of 44 articles, with 34 articles being included in the main review and another 2 articles included as Supporting Information materials. We found that psilocybin shows promise as a lead candidate molecule for treating a variety of neuropsychiatric conditions, albeit showing the most efficacy for depression. We discuss the experimental findings, and identify possible mechanisms whereby psilocybin could invoke therapeutic changes. Furthermore, we critically evaluate the between-study heterogeneity and possible future research avenues. Our review suggests that preclinical rodent models can provide valid and translatable tools for researching novel psilocybin-induced molecular and cellular mechanisms, and therapeutic outcomes.
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Affiliation(s)
- James J Gattuso
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Carey Wilson
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Thibault Renoir
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia
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Villiger D, Trachsel M. With great power comes great vulnerability: an ethical analysis of psychedelics' therapeutic mechanisms proposed by the REBUS hypothesis. JOURNAL OF MEDICAL ETHICS 2023; 49:826-832. [PMID: 37045591 DOI: 10.1136/jme-2022-108816] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 03/03/2023] [Indexed: 06/19/2023]
Abstract
Psychedelics are experiencing a renaissance in mental healthcare. In recent years, more and more early phase trials on psychedelic-assisted therapy have been conducted, with promising results overall. However, ethical analyses of this rediscovered form of treatment remain rare. The present paper contributes to the ethical inquiry of psychedelic-assisted therapy by analysing the ethical implications of its therapeutic mechanisms proposed by the relaxed beliefs under psychedelics (REBUS) hypothesis. In short, the REBUS hypothesis states that psychedelics make rigid beliefs revisable by increasing the influence of bottom-up input. Put differently, patients become highly suggestible and sensitive to context during a psychedelic session, amplifying therapeutic influence and effects. Due to that, patients are more vulnerable in psychedelic-assisted therapy than in other therapeutic interventions; they lose control during a psychedelic session and become dependent on the therapeutic setting (including the therapist). This enhanced vulnerability is ethically relevant and has been exploited by some therapists in the past. Therefore, patients in current research settings and starting mainstream medical settings need to be well informed about psychedelics' mechanisms and their implications to give valid informed consent to treatment. Furthermore, other security measures are warranted to protect patients from the vulnerability coming with psychedelic-assisted therapy.
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Affiliation(s)
- Daniel Villiger
- Department of Philosophy, University of Zurich, Zurich, Switzerland
| | - Manuel Trachsel
- Clinical Ethics Unit of University Hospital Basel and Psychiatric University Clinics, Basel, Switzerland
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9
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Bottemanne H, Berkovitch L, Gauld C, Balcerac A, Schmidt L, Mouchabac S, Fossati P. Storm on predictive brain: A neurocomputational account of ketamine antidepressant effect. Neurosci Biobehav Rev 2023; 154:105410. [PMID: 37793581 DOI: 10.1016/j.neubiorev.2023.105410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 08/24/2023] [Accepted: 09/26/2023] [Indexed: 10/06/2023]
Abstract
For the past decade, ketamine, an N-methyl-D-aspartate receptor (NMDAr) antagonist, has been considered a promising treatment for major depressive disorder (MDD). Unlike the delayed effect of monoaminergic treatment, ketamine may produce fast-acting antidepressant effects hours after a single administration at subanesthetic dose. Along with these antidepressant effects, it may also induce transient dissociative (disturbing of the sense of self and reality) symptoms during acute administration which resolve within hours. To understand ketamine's rapid-acting antidepressant effect, several biological hypotheses have been explored, but despite these promising avenues, there is a lack of model to understand the timeframe of antidepressant and dissociative effects of ketamine. In this article, we propose a neurocomputational account of ketamine's antidepressant and dissociative effects based on the Predictive Processing (PP) theory, a framework for cognitive and sensory processing. PP theory suggests that the brain produces top-down predictions to process incoming sensory signals, and generates bottom-up prediction errors (PEs) which are then used to update predictions. This iterative dynamic neural process would relies on N-methyl-D-aspartate (NMDAr) and α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic receptors (AMPAr), two major component of the glutamatergic signaling. Furthermore, it has been suggested that MDD is characterized by over-rigid predictions which cannot be updated by the PEs, leading to miscalibration of hierarchical inference and self-reinforcing negative feedback loops. Based on former empirical studies using behavioral paradigms, neurophysiological recordings, and computational modeling, we suggest that ketamine impairs top-down predictions by blocking NMDA receptors, and enhances presynaptic glutamate release and PEs, producing transient dissociative symptoms and fast-acting antidepressant effect in hours following acute administration. Moreover, we present data showing that ketamine may enhance a delayed neural plasticity pathways through AMPAr potentiation, triggering a prolonged antidepressant effect up to seven days for unique administration. Taken together, the two sides of antidepressant effects with distinct timeframe could constitute the keystone of antidepressant properties of ketamine. These PP disturbances may also participate to a ketamine-induced time window of mental flexibility, which can be used to improve the psychotherapeutic process. Finally, these proposals could be used as a theoretical framework for future research into fast-acting antidepressants, and combination with existing antidepressant and psychotherapy.
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Affiliation(s)
- Hugo Bottemanne
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Philosophy, Science Norm Democracy Research Unit, UMR, 8011, Paris, France; Sorbonne University, Department of Psychiatry, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.
| | - Lucie Berkovitch
- Saclay CEA Centre, Neurospin, Gif-Sur-Yvette Cedex, France; Department of Psychiatry, GHU Paris Psychiatrie et Neurosciences, Service Hospitalo-Universitaire, Paris, France
| | - Christophe Gauld
- Department of Child Psychiatry, CHU de Lyon, F-69000 Lyon, France; Institut des Sciences Cognitives Marc Jeannerod, UMR 5229 CNRS & Université Claude Bernard Lyon 1, F-69000 Lyon, France
| | - Alexander Balcerac
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Neurology, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Liane Schmidt
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France
| | - Stephane Mouchabac
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Psychiatry, Saint-Antoine Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Philippe Fossati
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Philosophy, Science Norm Democracy Research Unit, UMR, 8011, Paris, France
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Rijsketic DR, Casey AB, Barbosa DAN, Zhang X, Hietamies TM, Ramirez-Ovalle G, Pomrenze MB, Halpern CH, Williams LM, Malenka RC, Heifets BD. UNRAVELing the synergistic effects of psilocybin and environment on brain-wide immediate early gene expression in mice. Neuropsychopharmacology 2023; 48:1798-1807. [PMID: 37248402 PMCID: PMC10579391 DOI: 10.1038/s41386-023-01613-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/25/2023] [Accepted: 05/15/2023] [Indexed: 05/31/2023]
Abstract
The effects of context on the subjective experience of serotonergic psychedelics have not been fully examined in human neuroimaging studies, partly due to limitations of the imaging environment. Here, we administered saline or psilocybin to mice in their home cage or an enriched environment, immunofluorescently-labeled brain-wide c-Fos, and imaged iDISCO+ cleared tissue with light sheet fluorescence microscopy (LSFM) to examine the impact of environmental context on psilocybin-elicited neural activity at cellular resolution. Voxel-wise analysis of c-Fos-immunofluorescence revealed clusters of neural activity associated with main effects of context and psilocybin-treatment, which were validated with c-Fos+ cell density measurements. Psilocybin increased c-Fos expression in subregions of the neocortex, caudoputamen, central amygdala, and parasubthalamic nucleus while it decreased c-Fos in the hypothalamus, cortical amygdala, striatum, and pallidum in a predominantly context-independent manner. To gauge feasibility of future mechanistic studies on ensembles activated by psilocybin, we confirmed activity- and Cre-dependent genetic labeling in a subset of these neurons using TRAP2+/-;Ai14+ mice. Network analyses treating each psilocybin-sensitive cluster as a node indicated that psilocybin disrupted co-activity between highly correlated regions, reduced brain modularity, and dramatically attenuated intermodular co-activity. Overall, our results indicate that main effects of context and psilocybin were robust, widespread, and reorganized network architecture, whereas context×psilocybin interactions were surprisingly sparse.
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Affiliation(s)
- Daniel Ryskamp Rijsketic
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Austen B Casey
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Daniel A N Barbosa
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Xue Zhang
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, 94305, USA
| | - Tuuli M Hietamies
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Grecia Ramirez-Ovalle
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Matthew B Pomrenze
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, 94305, USA
- Nancy Pritzker Laboratory, Stanford University, Stanford, CA, 94305, USA
| | - Casey H Halpern
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Leanne M Williams
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, 94305, USA
- Sierra-Pacific Mental Illness Research, Education, and Clinical Center (MIRECC) Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Robert C Malenka
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, 94305, USA
- Nancy Pritzker Laboratory, Stanford University, Stanford, CA, 94305, USA
| | - Boris D Heifets
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, 94305, USA.
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11
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Rieser NM, Gubser LP, Moujaes F, Duerler P, Lewis CR, Michels L, Vollenweider FX, Preller KH. Psilocybin-induced changes in cerebral blood flow are associated with acute and baseline inter-individual differences. Sci Rep 2023; 13:17475. [PMID: 37838755 PMCID: PMC10576760 DOI: 10.1038/s41598-023-44153-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 10/04/2023] [Indexed: 10/16/2023] Open
Abstract
Research into the use of psilocybin for the treatment of psychiatric disorders is a growing field. Nevertheless, robust brain-behavior relationships linking psilocybin-induced brain changes to subjective drug-induced effects have not been established. Furthermore, it is unclear if the acute neural effects are dependent on individual heterogeneity in baseline characteristics. To address this, we assessed the effects of three oral doses of psilocybin vs. placebo on cerebral blood flow (CBF) using arterial spin labeling in healthy participants (N = 70; n = 31, 0.16 mg/kg; n = 10, 0.2 mg/kg; n = 29, 0.215 mg/kg). First, we quantified psilocybin-induced changes in relative and absolute CBF. Second, in an exploratory analysis, we assessed whether individual baseline characteristics and subjective psychedelic experience are associated with changes in CBF. Psychological and neurobiological baseline characteristics correlated with the psilocybin-induced reduction in relative CBF and the psilocybin-induced subjective experience. Furthermore, the psilocybin-induced subjective experience was associated with acute changes in relative and absolute CBF. The results demonstrated that inter-individual heterogeneity in the neural response to psilocybin is associated with baseline characteristics and shed light on the mechanisms underlying the psychedelic-induced altered state. Overall, these findings help guide the search for biomarkers, paving the way for a personalized medicine approach within the framework of psychedelic-assisted therapy.
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Affiliation(s)
- Nathalie M Rieser
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland.
| | - Ladina P Gubser
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland
| | - Flora Moujaes
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, 06510, USA
| | - Patricia Duerler
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland
| | - Candace R Lewis
- School of Life Sciences, Arizona State University, Tempe, AZ, 85281, USA
| | - Lars Michels
- Department of Neuroradiology, University Hospital Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
| | - Franz X Vollenweider
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland
| | - Katrin H Preller
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland
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12
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Buchborn T, Kettner HS, Kärtner L, Meinhardt MW. The ego in psychedelic drug action - ego defenses, ego boundaries, and the therapeutic role of regression. Front Neurosci 2023; 17:1232459. [PMID: 37869510 PMCID: PMC10587586 DOI: 10.3389/fnins.2023.1232459] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/18/2023] [Indexed: 10/24/2023] Open
Abstract
The ego is one of the most central psychological constructs in psychedelic research and a key factor in psychotherapy, including psychedelic-assisted forms of psychotherapy. Despite its centrality, the ego-construct remains ambiguous in the psychedelic literature. Therefore, we here review the theoretical background of the ego-construct with focus on its psychodynamic conceptualization. We discuss major functions of the ego including ego boundaries, defenses, and synthesis, and evaluate the role of the ego in psychedelic drug action. According to the psycholytic paradigm, psychedelics are capable of inducing regressed states of the ego that are less protected by the ego's usual defensive apparatus. In such states, core early life conflicts may emerge that have led to maladaptive ego patterns. We use the psychodynamic term character in this paper as a potential site of change and rearrangement; character being the chronic and habitual patterns the ego utilizes to adapt to the everyday challenges of life, including a preferred set of defenses. We argue that in order for psychedelic-assisted therapy to successfully induce lasting changes to the ego's habitual patterns, it must psycholytically permeate the characterological core of the habits. The primary working principle of psycholytic therapy therefore is not the state of transient ego regression alone, but rather the regressively favored emotional integration of those early life events that have shaped the foundation, development, and/or rigidification of a person's character - including his or her defense apparatus. Aiming for increased flexibility of habitual ego patterns, the psycholytic approach is generally compatible with other forms of psychedelic-assisted therapy, such as third wave cognitive behavioral approaches.
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Affiliation(s)
- Tobias Buchborn
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Hannes S. Kettner
- Centre for Psychedelic Research, Department of Medicine, Imperial College London, London, United Kingdom
- Psychedelics Division, Neuroscape, Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
| | - Laura Kärtner
- Centre for Psychedelic Research, Department of Medicine, Imperial College London, London, United Kingdom
- Department of Molecular Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Marcus W. Meinhardt
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
- Department of Molecular Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
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13
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Syed OA, Tsang B, Gerlai R. The zebrafish for preclinical psilocybin research. Neurosci Biobehav Rev 2023; 153:105381. [PMID: 37689090 DOI: 10.1016/j.neubiorev.2023.105381] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/25/2023] [Accepted: 09/01/2023] [Indexed: 09/11/2023]
Abstract
In this review, we discuss the possible utility of zebrafish in research on psilocybin, a psychedelic drug whose recreational use as well as possible clinical application are gaining increasing interest. First, we review behavioral tests with zebrafish, focussing on anxiety and social behavior, which have particular relevance in the context of psilocybin research. Next, we briefly consider methods of genetic manipulations with which psilocybin's phenotypical effects and underlying mechanisms may be investigated in zebrafish. We briefly review the known mechanisms of psilocybin, and also discuss what we know about its safety and toxicity profile. Last, we discuss examples of how psilocybin may be employed for testing treatment efficacy in preclinical research for affective disorders in zebrafish. We conclude that zebrafish has a promising future in preclinical research on psychedelic drugs.
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Affiliation(s)
- Omer A Syed
- Department of Biology, University of Toronto Mississauga, Canada.
| | - Benjamin Tsang
- Department of Cell & Systems Biology, University of Toronto, Canada.
| | - Robert Gerlai
- Department of Cell & Systems Biology, University of Toronto, Canada; Department of Psychology, University of Toronto Mississauga, Canada.
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14
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Egger K, Gudmundsen F, Jessen NS, Baun C, Poetzsch SN, Shalgunov V, Herth MM, Quednow BB, Martin-Soelch C, Dornbierer D, Scheidegger M, Cumming P, Palner M. A pilot study of cerebral metabolism and serotonin 5-HT 2A receptor occupancy in rats treated with the psychedelic tryptamine DMT in conjunction with the MAO inhibitor harmine. Front Pharmacol 2023; 14:1140656. [PMID: 37841918 PMCID: PMC10568461 DOI: 10.3389/fphar.2023.1140656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 09/19/2023] [Indexed: 10/17/2023] Open
Abstract
Rationale: The psychedelic effects of the traditional Amazonian botanical decoction known as ayahuasca are often attributed to agonism at brain serotonin 5-HT2A receptors by N,N-dimethyltryptamine (DMT). To reduce first pass metabolism of oral DMT, ayahuasca preparations additionally contain reversible monoamine oxidase A (MAO-A) inhibitors, namely β-carboline alkaloids such as harmine. However, there is lacking biochemical evidence to substantiate this pharmacokinetic potentiation of DMT in brain via systemic MAO-A inhibition. Objectives: We measured the pharmacokinetic profile of harmine and/or DMT in rat brain, and tested for pharmacodynamic effects on brain glucose metabolism and DMT occupancy at brain serotonin 5-HT2A receptors. Methods: We first measured brain concentrations of harmine and DMT after treatment with harmine and/or DMT at low sub-cutaneous doses (1 mg/kg each) or harmine plus DMT at moderate doses (3 mg/kg each). In the same groups of rats, we also measured ex vivo the effects of these treatments on the availability of serotonin 5-HT2A receptors in frontal cortex. Finally, we explored effects of DMT and/or harmine (1 mg/kg each) on brain glucose metabolism with [18F]FDG-PET. Results: Results confirmed that co-administration of harmine inhibited the formation of the DMT metabolite indole-3-acetic acid (3-IAA) in brain, while correspondingly increasing the cerebral availability of DMT. However, we were unable to detect any significant occupancy by DMT at 5-HT2A receptors measured ex vivo, despite brain DMT concentrations as high as 11.3 µM. We did not observe significant effects of low dose DMT and/or harmine on cerebral [18F]FDG-PET uptake. Conclusion: These preliminary results call for further experiments to establish the dose-dependent effects of harmine/DMT on serotonin receptor occupancy and cerebral metabolism.
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Affiliation(s)
- Klemens Egger
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
- Department of Nuclear Medicine, Bern University Hospital, Bern, Switzerland
| | - Frederik Gudmundsen
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
- Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark
| | - Naja Støckel Jessen
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
- Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Christina Baun
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
- Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark
| | - Sandra N. Poetzsch
- Department of Forensic Pharmacology and Toxicology, Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Vladimir Shalgunov
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital, Copenhagen, Denmark
| | - Matthias M. Herth
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital, Copenhagen, Denmark
| | - Boris B. Quednow
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
| | | | - Dario Dornbierer
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Milan Scheidegger
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
| | - Paul Cumming
- Department of Nuclear Medicine, Bern University Hospital, Bern, Switzerland
- School of Psychology and Counselling, Queensland University of Technology, Brisbane, Australia
| | - Mikael Palner
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
- Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark
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15
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Yuan L, Mao G, Zhang Y, Xu Y, Chen Q, Shan B, Cui T, Ai L. Typical metabolic pattern of 18F-FDG PET in Anti-NMDAR encephalitis in the acute and subacute phases and its correlation with T2 FLAIR-MRI features. BMC Neurosci 2023; 24:51. [PMID: 37749547 PMCID: PMC10521454 DOI: 10.1186/s12868-023-00823-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 09/19/2023] [Indexed: 09/27/2023] Open
Abstract
BACKGROUND/AIMS Early diagnosis of Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis with non-invasive imaging modalities benefiting is crucial to guarantee prompt treatments decision-making and good prognosis for patients. The present study aimed to explore the correlation of MRI features with brain metabolism characteristics of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) and to describe the metabolic patterns in Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis at acute and subacute phases. Twenty-four patients with anti-NMDAR encephalitis confirmed by serum and/or CSF tests at acute and subacute phases, 9 females and 15 males, with an age range of 6-80 years, were enrolled in this retrospective study as encephalitis group. 18F-FDG PET and MRI findings of all patients were investigated and interpreted with visual analysis. Chi-square test was performed to compare the diagnostic sensitivity between MRI and PET. Independent sample t-test was used to compare the standardized uptake value ratio (SUVR) of each ROI between the encephalitis group and control group, which consisted of 24 healthy volunteers of the same age and gender. RESULTS There was no statistical difference in the diagnostic sensitivity between FDG PET (23/24, 95.83%) and MRI (18/24, 75.00%) in anti-NMDAR encephalitis patients (P > 0.05). Three categories of abnormalities shown on T2 FLAIR, including shallow of sulci and swelling of brain tissue, increased signal in the sulci, increased signal on brain gray matter or adjacent white matter presented hypermetabolism on PET, excepting increased signal in brain linear structure with hypometabolism of the basal ganglia on PET. We identified 19 brain regions with hypermetabolism and 16 brain regions with hypometabolism that exhibited statistically significant changes in SUVRs between anti-NMDAR encephalitis group and control group (FDR P < 0.05). CONCLUSION Anteroposterior glucose metabolism gradient (frontal-temporal/parietal-occipital) is proved to be a typical pattern of anti-NMDAR encephalitis at the acute and subacute phases in both visual and statistical testing. Interestingly, the pattern is also commonly found in the anterior and posterior portions of the parietal lobe and cingular cortex, which may be a potential indicator for the diagnosis of this disorder. In addition, MRI is an important and reliable neuroimaging modality to assist in the correct evaluation of activity changes on individual 18F-FDG PET.
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Affiliation(s)
- Leilei Yuan
- Department of Nuclear Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Guangjuan Mao
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
- School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yudi Zhang
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, China
| | - Yang Xu
- Department of Nuclear Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Qian Chen
- Department of Nuclear Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Baoci Shan
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
- School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tao Cui
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China.
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China.
| | - Lin Ai
- Department of Nuclear Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China.
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16
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Sharma P, Nguyen QA, Matthews SJ, Carpenter E, Mathews DB, Patten CA, Hammond CJ. Psilocybin history, action and reaction: A narrative clinical review. J Psychopharmacol 2023; 37:849-865. [PMID: 37650489 DOI: 10.1177/02698811231190858] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Hallucinogenic mushrooms have been used in religious and cultural ceremonies for centuries. Of late, psilocybin, the psychoactive compound in hallucinogenic mushrooms, has received increased public interest as a novel drug for treating mood and substance use disorders (SUDs). In addition, in recent years, some states in the United States have legalized psilocybin for medical and recreational use. Given this, clinicians need to understand the potential benefits and risks related to using psilocybin for therapeutic purposes so that they can accurately advise patients. This expert narrative review summarizes the scientific basis and clinical evidence on the safety and efficacy of psilocybin-assisted therapy for treating psychiatric disorders and SUDs. The results of this review are structured as a more extensive discussion about psilocybin's history, putative mechanisms of action, and recent legislative changes to its legal status. There is modest evidence of psilocybin-assisted therapy for treating depression and anxiety disorders. In addition, early data suggest that psilocybin-assisted therapy may effectively reduce harmful drinking in patients with alcohol use disorders. The evidence further suggests psilocybin, when administered under supervision (psilocybin-assisted therapy), the side effects experienced are mild and transient. The occurrence of severe adverse events following psilocybin administration is uncommon. Still, a recent clinical trial found that individuals in the psilocybin arm had increased suicidal ideations and non-suicidal self-injurious behaviors. Given this, further investigation into the safety and efficacy of psilocybin-assisted therapy is warranted to determine which patient subgroups are most likely to benefit and which are most likely to experience adverse outcomes related to its use.
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Affiliation(s)
- Pravesh Sharma
- Department of Psychiatry and Psychology, Mayo Clinic Health System, Eau Claire, WI, USA
- Behavioral Health Research Program, Department of Psychology and Psychiatry Research, Mayo Clinic, Rochester, MN, USA
| | - Quang Anh Nguyen
- Behavioral Health Research Program, Department of Psychology and Psychiatry Research, Mayo Clinic, Rochester, MN, USA
| | - Sadie J Matthews
- Department of Psychology, University of Wisconsin (Eau Claire), Eau Claire, WI, USA
| | | | - Douglas B Mathews
- Department of Psychology, University of Wisconsin (Eau Claire), Eau Claire, WI, USA
| | - Christi A Patten
- Behavioral Health Research Program, Department of Psychology and Psychiatry Research, Mayo Clinic, Rochester, MN, USA
| | - Christopher J Hammond
- Division of Child and Adolescent Psychiatry, Johns Hopkins School of Medicine, Baltimore, MD, USA
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17
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Siegel JS, Subramanian S, Perry D, Kay B, Gordon E, Laumann T, Reneau R, Gratton C, Horan C, Metcalf N, Chacko R, Schweiger J, Wong D, Bender D, Padawer-Curry J, Raison C, Raichle M, Lenze EJ, Snyder AZ, Dosenbach NUF, Nicol G. Psilocybin desynchronizes brain networks. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.08.22.23294131. [PMID: 37701731 PMCID: PMC10493007 DOI: 10.1101/2023.08.22.23294131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
1The relationship between the acute effects of psychedelics and their persisting neurobiological and psychological effects is poorly understood. Here, we tracked brain changes with longitudinal precision functional mapping in healthy adults before, during, and for up to 3 weeks after oral psilocybin and methylphenidate (17 MRI visits per participant) and again 6+ months later. Psilocybin disrupted connectivity across cortical networks and subcortical structures, producing more than 3-fold greater acute changes in functional networks than methylphenidate. These changes were driven by desynchronization of brain activity across spatial scales (area, network, whole brain). Psilocybin-driven desynchronization was observed across association cortex but strongest in the default mode network (DMN), which is connected to the anterior hippocampus and thought to create our sense of self. Performing a perceptual task reduced psilocybin-induced network changes, suggesting a neurobiological basis for grounding, connecting with physical reality during psychedelic therapy. The acute brain effects of psilocybin are consistent with distortions of space-time and the self. Psilocybin induced persistent decrease in functional connectivity between the anterior hippocampus and cortex (and DMN in particular), lasting for weeks but normalizing after 6 months. Persistent suppression of hippocampal-DMN connectivity represents a candidate neuroanatomical and mechanistic correlate for psilocybin's pro-plasticity and anti-depressant effects.
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18
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Zafar R, Siegel M, Harding R, Barba T, Agnorelli C, Suseelan S, Roseman L, Wall M, Nutt DJ, Erritzoe D. Psychedelic therapy in the treatment of addiction: the past, present and future. Front Psychiatry 2023; 14:1183740. [PMID: 37377473 PMCID: PMC10291338 DOI: 10.3389/fpsyt.2023.1183740] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/15/2023] [Indexed: 06/29/2023] Open
Abstract
Psychedelic therapy has witnessed a resurgence in interest in the last decade from the scientific and medical communities with evidence now building for its safety and efficacy in treating a range of psychiatric disorders including addiction. In this review we will chart the research investigating the role of these interventions in individuals with addiction beginning with an overview of the current socioeconomic impact of addiction, treatment options, and outcomes. We will start by examining historical studies from the first psychedelic research era of the mid-late 1900s, followed by an overview of the available real-world evidence gathered from naturalistic, observational, and survey-based studies. We will then cover modern-day clinical trials of psychedelic therapies in addiction from first-in-human to phase II clinical trials. Finally, we will provide an overview of the different translational human neuropsychopharmacology techniques, including functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), that can be applied to foster a mechanistic understanding of therapeutic mechanisms. A more granular understanding of the treatment effects of psychedelics will facilitate the optimisation of the psychedelic therapy drug development landscape, and ultimately improve patient outcomes.
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Affiliation(s)
- Rayyan Zafar
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- Neuropsychopharmacology Unit, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Maxim Siegel
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- Neuropsychopharmacology Unit, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Rebecca Harding
- Clinical Psychopharmacology Unit, University College London, London, United Kingdom
| | - Tommaso Barba
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- Neuropsychopharmacology Unit, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Claudio Agnorelli
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- Neuropsychopharmacology Unit, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Shayam Suseelan
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- Neuropsychopharmacology Unit, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Leor Roseman
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- Neuropsychopharmacology Unit, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Matthew Wall
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- Neuropsychopharmacology Unit, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- Invicro, London, United Kingdom
| | - David John Nutt
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- Neuropsychopharmacology Unit, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - David Erritzoe
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- Neuropsychopharmacology Unit, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
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19
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Liu J, Wang Y, Xia K, Wu J, Zheng D, Cai A, Yan H, Su R. Acute psilocybin increased cortical activities in rats. Front Neurosci 2023; 17:1168911. [PMID: 37287797 PMCID: PMC10243528 DOI: 10.3389/fnins.2023.1168911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 05/04/2023] [Indexed: 06/09/2023] Open
Abstract
Psilocybin, a naturally occurring hallucinogenic component of magic mushrooms, has significant psychoactive effects in both humans and rodents. But the underlying mechanisms are not fully understood. Blood-oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is a useful tool in many preclinical and clinical trials to investigate psilocybin-induced changes of brain activity and functional connectivity (FC) due to its noninvasive nature and widespread availability. However, fMRI effects of psilocybin on rats have not been carefully investigated. This study aimed to explore how psilocybin affects resting-state brain activity and FC, through a combination of BOLD fMRI and immunofluorescence (IF) of EGR1, an immediate early gene (IEG) closely related to depressive symptoms. Ten minutes after psilocybin hydrochloride injection (2.0 mg/kg, i.p.), positive brain activities were observed in the frontal, temporal, and parietal cortex (including the cingulate cortex and retrosplenial cortex), hippocampus, and striatum. And a region-of-interest (ROI) -wise FC analysis matrix suggested increased interconnectivity of several regions, such as the cingulate cortex, dorsal striatum, prelimbic, and limbic regions. Further seed-based analyses revealed increased FC of cingulate cortex within the cortical and striatal areas. Consistently, acute psilocybin increased the EGR1 level throughout the brain, indicating a consistent activation thought the cortical and striatal areas. In conclusion, the psilocybin-induced hyperactive state of rats is congruent to that of humans, and may be responsible for its pharmacological effects.
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Affiliation(s)
- Junhong Liu
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Yuanyuan Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China
- Nanjing University of Chinese Medicine, Nanjing, China
| | - Ke Xia
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Jinfeng Wu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Danhao Zheng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Aoling Cai
- The Affiliated Changzhou Second People's Hospital of Nanjing Medical University, Changzhou Second People's Hospital, Changzhou Medical Center, Nanjing Medical University, Changzhou, China
| | - Haitao Yan
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Ruibin Su
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China
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20
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Fissler P, Vandersmissen A, Filippi M, Mavioglu RN, Scholkmann F, Karabatsiakis A, Krähenmann R. Effects of serotonergic psychedelics on mitochondria: Transdiagnostic implications for mitochondria-related pathologies. J Psychopharmacol 2023:2698811231164707. [PMID: 37122193 DOI: 10.1177/02698811231164707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The use of serotonergic psychedelics has gained increasing attention in research, clinical practice and society. Growing evidence suggests fast-acting, transdiagnostic health benefits of these 5-hydroxytryptamine 2A receptor agonists. Here, we provide a brief overview of their benefits for psychological, cardiovascular, metabolic, neurodegenerative, and immunological pathologies. We then review their effect on mitochondria including mitochondrial biogenesis, functioning and transport. Mitochondrial dysregulation is a transdiagnostic mechanism that contributes to the aforementioned pathologies. Hence, we postulate that psychedelic-induced effects on mitochondria partially underlie their transdiagnostic benefits. Based on this assumption, we propose new treatment indications for psychedelics and that the health benefits induced by psychedelics depend on patient-specific mitochondrial dysregulation.
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Affiliation(s)
- Patrick Fissler
- Psychiatric Services Thurgau, Spital Thurgau AG, Münsterlingen, Switzerland
- University Hospital for Psychiatry and Psychotherapy, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Anja Vandersmissen
- Psychiatric Services Thurgau, Spital Thurgau AG, Münsterlingen, Switzerland
- University Hospital for Psychiatry and Psychotherapy, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Marco Filippi
- Psychiatric Services Thurgau, Spital Thurgau AG, Münsterlingen, Switzerland
- University Hospital for Psychiatry and Psychotherapy, Paracelsus Medical University Salzburg, Salzburg, Austria
| | | | - Felix Scholkmann
- Biomedical Optics Research Laboratory, Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Alexander Karabatsiakis
- Department of Psychology, Clinical Psychology II, University of Innsbruck, Innsbruck, Austria
| | - Rainer Krähenmann
- Psychiatric Services Thurgau, Spital Thurgau AG, Münsterlingen, Switzerland
- University Hospital for Psychiatry and Psychotherapy, Paracelsus Medical University Salzburg, Salzburg, Austria
- Department of Psychiatry, Psychotherapy and Psychosomatics, University of Zürich, Zürich, Switzerland
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21
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Gattuso JJ, Perkins D, Ruffell S, Lawrence AJ, Hoyer D, Jacobson LH, Timmermann C, Castle D, Rossell SL, Downey LA, Pagni BA, Galvão-Coelho NL, Nutt D, Sarris J. Default Mode Network Modulation by Psychedelics: A Systematic Review. Int J Neuropsychopharmacol 2023; 26:155-188. [PMID: 36272145 PMCID: PMC10032309 DOI: 10.1093/ijnp/pyac074] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022] Open
Abstract
Psychedelics are a unique class of drug that commonly produce vivid hallucinations as well as profound psychological and mystical experiences. A grouping of interconnected brain regions characterized by increased temporal coherence at rest have been termed the Default Mode Network (DMN). The DMN has been the focus of numerous studies assessing its role in self-referencing, mind wandering, and autobiographical memories. Altered connectivity in the DMN has been associated with a range of neuropsychiatric conditions such as depression, anxiety, post-traumatic stress disorder, attention deficit hyperactive disorder, schizophrenia, and obsessive-compulsive disorder. To date, several studies have investigated how psychedelics modulate this network, but no comprehensive review, to our knowledge, has critically evaluated how major classical psychedelic agents-lysergic acid diethylamide, psilocybin, and ayahuasca-modulate the DMN. Here we present a systematic review of the knowledge base. Across psychedelics there is consistent acute disruption in resting state connectivity within the DMN and increased functional connectivity between canonical resting-state networks. Various models have been proposed to explain the cognitive mechanisms of psychedelics, and in one model DMN modulation is a central axiom. Although the DMN is consistently implicated in psychedelic studies, it is unclear how central the DMN is to the therapeutic potential of classical psychedelic agents. This article aims to provide the field with a comprehensive overview that can propel future research in such a way as to elucidate the neurocognitive mechanisms of psychedelics.
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Affiliation(s)
- James J Gattuso
- MDHS, University of Melbourne, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Daniel Perkins
- Psychae Institute, Melbourne, Victoria, Australia
- MDHS, University of Melbourne, Parkville, Victoria, Australia
- School of Social and Political Science, University of Melbourne, Australia
- Centre for Mental Health, Swinburne University, Hawthorn, Victoria, Australia
| | - Simon Ruffell
- The Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK
| | - Andrew J Lawrence
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Daniel Hoyer
- MDHS, University of Melbourne, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, California, USA
| | - Laura H Jacobson
- MDHS, University of Melbourne, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | | | - David Castle
- Department of Psychiatry, University of Toronto, Canada
| | - Susan L Rossell
- Centre for Mental Health, Swinburne University, Hawthorn, Victoria, Australia
| | - Luke A Downey
- Centre for Human Psychopharmacology, Swinburne University, Hawthorn, Victoria, Australia
| | - Broc A Pagni
- College of Health Solutions, Arizona State University, Tempe, Arizona, USA
| | - Nicole L Galvão-Coelho
- Department of Physiology and Behavior, Universidade Federal do Rio Grande do Norte, Brazil
- NICM Health Research Institute, Western Sydney University, Westmead, New South Wales, Australia
| | - David Nutt
- Centre for Psychedelic Research, Division of Psychiatry, Imperial College London, UK
| | - Jerome Sarris
- Psychae Institute, Melbourne, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- NICM Health Research Institute, Western Sydney University, Westmead, New South Wales, Australia
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22
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Wießner I, Falchi M, Palhano-Fontes F, Feilding A, Ribeiro S, Tófoli LF. LSD, madness and healing: Mystical experiences as possible link between psychosis model and therapy model. Psychol Med 2023; 53:1151-1165. [PMID: 34253268 DOI: 10.1017/s0033291721002531] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND For a century, psychedelics have been investigated as models of psychosis for demonstrating phenomenological similarities with psychotic experiences and as therapeutic models for treating depression, anxiety, and substance use disorders. This study sought to explore this paradoxical relationship connecting key parameters of the psychotic experience, psychotherapy, and psychedelic experience. METHODS In a randomized, double-blind, placebo-controlled, crossover design, 24 healthy volunteers received 50 μg d-lysergic acid diethylamide (LSD) or inactive placebo. Psychotic experience was assessed by aberrant salience (Aberrant Salience Inventory, ASI), therapeutic potential by suggestibility (Creative Imagination Scale, CIS) and mindfulness (Five Facet Mindfulness Questionnaire, FFMQ; Mindful Attention Awareness Scale, MAAS; Experiences Questionnaire, EQ), and psychedelic experience by four questionnaires (Altered State of Consciousness Questionnaire, ASC; Mystical Experiences Questionnaire, MEQ; Challenging Experiences Questionnaire, CEQ; Ego-Dissolution Inventory, EDI). Relationships between LSD-induced effects were examined. RESULTS LSD induced psychedelic experiences, including alteration of consciousness, mystical experiences, ego-dissolution, and mildly challenging experiences, increased aberrant salience and suggestibility, but not mindfulness. LSD-induced aberrant salience correlated highly with complex imagery, mystical experiences, and ego-dissolution. LSD-induced suggestibility correlated with no other effects. Individual mindfulness changes correlated with aspects of aberrant salience and psychedelic experience. CONCLUSIONS The LSD state resembles a psychotic experience and offers a tool for healing. The link between psychosis model and therapeutic model seems to lie in mystical experiences. The results point to the importance of meaning attribution for the LSD psychosis model and indicate that psychedelic-assisted therapy might benefit from therapeutic suggestions fostering mystical experiences.
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Affiliation(s)
- Isabel Wießner
- Department of Medical Psychology and Psychiatry, School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
- Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
| | - Marcelo Falchi
- Department of Medical Psychology and Psychiatry, School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
- Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
| | - Fernanda Palhano-Fontes
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | | | - Sidarta Ribeiro
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Luís Fernando Tófoli
- Department of Medical Psychology and Psychiatry, School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
- Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
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23
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Rijsketic DR, Casey AB, Barbosa DA, Zhang X, Hietamies TM, Ramirez-Ovalle G, Pomrenze M, Halpern CH, Williams LM, Malenka RC, Heifets BD. UNRAVELing the synergistic effects of psilocybin and environment on brain-wide immediate early gene expression in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.19.528997. [PMID: 36865251 PMCID: PMC9980055 DOI: 10.1101/2023.02.19.528997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The effects of context on the subjective experience of serotonergic psychedelics have not been fully examined in human neuroimaging studies, partly due to limitations of the imaging environment. Here, we administered saline or psilocybin to mice in their home cage or an enriched environment, immunofluorescently-labeled brain-wide c-Fos, and imaged cleared tissue with light sheet microscopy to examine the impact of context on psilocybin-elicited neural activity at cellular resolution. Voxel-wise analysis of c-Fos-immunofluorescence revealed differential neural activity, which we validated with c-Fos + cell density measurements. Psilocybin increased c-Fos expression in the neocortex, caudoputamen, central amygdala, and parasubthalamic nucleus and decreased c-Fos in the hypothalamus, cortical amygdala, striatum, and pallidum. Main effects of context and psilocybin-treatment were robust, widespread, and spatially distinct, whereas interactions were surprisingly sparse.
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Affiliation(s)
- Daniel Ryskamp Rijsketic
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Austen B. Casey
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Daniel A.N. Barbosa
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Xue Zhang
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
| | - Tuuli M. Hietamies
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Grecia Ramirez-Ovalle
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Matthew Pomrenze
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
- Nancy Pritzker Laboratory, Stanford University, Stanford, CA 94305, USA
| | - Casey H. Halpern
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Leanne M. Williams
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
- Sierra-Pacific Mental Illness Research, Education, and Clinical Center (MIRECC) Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Robert C. Malenka
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
- Nancy Pritzker Laboratory, Stanford University, Stanford, CA 94305, USA
| | - Boris D. Heifets
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
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24
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Stoliker D, Novelli L, Vollenweider FX, Egan GF, Preller KH, Razi A. Effective Connectivity of Functionally Anticorrelated Networks Under Lysergic Acid Diethylamide. Biol Psychiatry 2023; 93:224-232. [PMID: 36270812 DOI: 10.1016/j.biopsych.2022.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 12/27/2022]
Abstract
BACKGROUND Classic psychedelic-induced ego dissolution involves a shift in the sense of self and a blurring of the boundary between the self and the world. A similar phenomenon is identified in psychopathology and is associated with the balance of anticorrelated activity between the default mode network, which directs attention inward, and the salience network, which recruits the dorsal attention network to direct attention outward. METHODS To test whether changes in anticorrelated networks underlie the peak effects of lysergic acid diethylamide (LSD), we applied dynamic causal modeling to infer effective connectivity of resting-state functional magnetic resonance imaging scans from a study of 25 healthy adults who were administered 100 μg of LSD or placebo. RESULTS We found that inhibitory effective connectivity from the salience network to the default mode network became excitatory, and inhibitory effective connectivity from the default mode network to the dorsal attention network decreased under the peak effect of LSD. CONCLUSIONS The effective connectivity changes we identified may reflect diminution of the functional anticorrelation between resting-state networks that may be a key neural mechanism of LSD and underlie ego dissolution. Our findings suggest that changes to the sense of self and subject-object boundaries across different states of consciousness may depend upon the organized balance of effective connectivity of resting-state networks.
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Affiliation(s)
- Devon Stoliker
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia.
| | - Leonardo Novelli
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia
| | - Franz X Vollenweider
- Department of Psychiatry, Psychotherapy & Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Gary F Egan
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia; Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia
| | - Katrin H Preller
- Department of Psychiatry, Psychotherapy & Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Adeel Razi
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia; Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia; Wellcome Centre for Human Neuroimaging, University College London, London, United Kingdom; CIFAR Azrieli Global Scholars Program, CIFAR, Toronto, Ontario, Canada
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25
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Scholkmann F, Vollenweider FX. Psychedelics and fNIRS neuroimaging: exploring new opportunities. NEUROPHOTONICS 2023; 10:013506. [PMID: 36474478 PMCID: PMC9717437 DOI: 10.1117/1.nph.10.1.013506] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
In this Outlook paper, we explain to the optical neuroimaging community as well as the psychedelic research community the great potential of using optical neuroimaging with functional near-infrared spectroscopy (fNIRS) to further explore the changes in brain activity induced by psychedelics. We explain why we believe now is the time to exploit the momentum of the current resurgence of research on the effects of psychedelics and the momentum of the increasing progress and popularity of the fNIRS technique to establish fNIRS in psychedelic research. With this article, we hope to contribute to this development.
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Affiliation(s)
- Felix Scholkmann
- University Hospital Zurich, University of Zurich, Biomedical Optics Research Laboratory, Department of Neonatology, Zurich, Switzerland
- University of Bern, Institute of Complementary and Integrative Medicine, Bern, Switzerland
| | - Franz X. Vollenweider
- University Hospital of Psychiatry, University of Zurich, Neuropsychopharmacology and Brain Imaging, Department of Psychiatry, Psychotherapy and Psychosomatics, Zurich, Switzerland
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26
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Ona G, Kohek M, Bouso JC. The illusion of knowledge in the emerging field of psychedelic research. NEW IDEAS IN PSYCHOLOGY 2022. [DOI: 10.1016/j.newideapsych.2022.100967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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27
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Strauss D, Ghosh S, Murray Z, Gryzenhout M. Psilocybin containing mushrooms: a rapidly developing biotechnology industry in the psychiatry, biomedical and nutraceutical fields. 3 Biotech 2022; 12:339. [PMID: 36340802 PMCID: PMC9633885 DOI: 10.1007/s13205-022-03355-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 09/08/2022] [Indexed: 11/06/2022] Open
Abstract
Humans have collected and used hallucinogenic mushrooms for ethnic medicinal, recreational, and religious purposes since before recorded history. Currently, the use of these mushrooms is illegal in most countries, but where their use is legal they are applied as self medication. Psilocybin and psilocin, two psychoactive alkaloids, are naturally synthesized by hallucinogenic mushrooms. The chemical structure of these compounds are similar to the neurotransmitter serotonin. Activation of this system by psilocybin and psilocin may produce temporary changes in the brain that induce hallucinations and feelings of euphoria. Adjustment of the serotonin system in this way can moderate symptoms of related mental disorders. This review summarizes relevant and current information regarding the discovery of hallucinogenic mushrooms and their contained psychoactive compounds, the events that lead to their criminalization and decriminilization, and the state of knowledge of psilocybin, psilocin, and derivatives. Last, research on the psychoactive properties of these mushrooms is placed in perspective to possible applications for human dysfunctions.
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Affiliation(s)
- Dominique Strauss
- Department of Genetics, Natural and Agricultural Sciences, University of Free State, PO Box 339, Bloemfontein, 9301 South Africa
| | - Soumya Ghosh
- Department of Genetics, Natural and Agricultural Sciences, University of Free State, PO Box 339, Bloemfontein, 9301 South Africa
| | - Zurika Murray
- Department of Genetics, Natural and Agricultural Sciences, University of Free State, PO Box 339, Bloemfontein, 9301 South Africa
| | - Marieka Gryzenhout
- Department of Genetics, Natural and Agricultural Sciences, University of Free State, PO Box 339, Bloemfontein, 9301 South Africa
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28
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Kwan AC, Olson DE, Preller KH, Roth BL. The neural basis of psychedelic action. Nat Neurosci 2022; 25:1407-1419. [PMID: 36280799 PMCID: PMC9641582 DOI: 10.1038/s41593-022-01177-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 09/06/2022] [Indexed: 01/13/2023]
Abstract
Psychedelics are serotonin 2A receptor agonists that can lead to profound changes in perception, cognition and mood. In this review, we focus on the basic neurobiology underlying the action of psychedelic drugs. We first discuss chemistry, highlighting the diversity of psychoactive molecules and the principles that govern their potency and pharmacokinetics. We describe the roles of serotonin receptors and their downstream molecular signaling pathways, emphasizing key elements for drug discovery. We consider the impact of psychedelics on neuronal spiking dynamics in several cortical and subcortical regions, along with transcriptional changes and sustained effects on structural plasticity. Finally, we summarize neuroimaging results that pinpoint effects on association cortices and thalamocortical functional connectivity, which inform current theories of psychedelic action. By synthesizing knowledge across the chemical, molecular, neuronal, and network levels, we hope to provide an integrative perspective on the neural mechanisms responsible for the acute and enduring effects of psychedelics on behavior.
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Affiliation(s)
- Alex C. Kwan
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA,Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA,Correspondence: ; ; ;
| | - David E. Olson
- Department of Chemistry, University of California, Davis, Davis, CA, USA,Department of Biochemistry & Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA, USA,Center for Neuroscience, University of California, Davis, Davis, CA, USA,Correspondence: ; ; ;
| | - Katrin H. Preller
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital, University of Zurich, Zurich, Switzerland.,Correspondence: ; ; ;
| | - Bryan L. Roth
- Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA.,Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA.,Psychoactive Drug Screening Program, National Institute of Mental Health, School of Medicine, University of North Carolina, Chapel Hill, NC, USA.,Correspondence: ; ; ;
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29
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Stoliker D, Egan GF, Friston KJ, Razi A. Neural Mechanisms and Psychology of Psychedelic Ego Dissolution. Pharmacol Rev 2022; 74:876-917. [PMID: 36786290 DOI: 10.1124/pharmrev.121.000508] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 06/26/2022] [Accepted: 06/29/2022] [Indexed: 11/22/2022] Open
Abstract
Neuroimaging studies of psychedelics have advanced our understanding of hierarchical brain organization and the mechanisms underlying their subjective and therapeutic effects. The primary mechanism of action of classic psychedelics is binding to serotonergic 5-HT2A receptors. Agonist activity at these receptors leads to neuromodulatory changes in synaptic efficacy that can have a profound effect on hierarchical message-passing in the brain. Here, we review the cognitive and neuroimaging evidence for the effects of psychedelics: in particular, their influence on selfhood and subject-object boundaries-known as ego dissolution-surmised to underwrite their subjective and therapeutic effects. Agonism of 5-HT2A receptors, located at the apex of the cortical hierarchy, may have a particularly powerful effect on sentience and consciousness. These effects can endure well after the pharmacological half-life, suggesting that psychedelics may have effects on neural plasticity that may play a role in their therapeutic efficacy. Psychologically, this may be accompanied by a disarming of ego resistance that increases the repertoire of perceptual hypotheses and affords alternate pathways for thought and behavior, including those that undergird selfhood. We consider the interaction between serotonergic neuromodulation and sentience through the lens of hierarchical predictive coding, which speaks to the value of psychedelics in understanding how we make sense of the world and specific predictions about effective connectivity in cortical hierarchies that can be tested using functional neuroimaging. SIGNIFICANCE STATEMENT: Classic psychedelics bind to serotonergic 5-HT2A receptors. Their agonist activity at these receptors leads to neuromodulatory changes in synaptic efficacy, resulting in a profound effect on information processing in the brain. Here, we synthesize an abundance of brain imaging research with pharmacological and psychological interpretations informed by the framework of predictive coding. Moreover, predictive coding is suggested to offer more sophisticated interpretations of neuroimaging findings by bridging the role between the 5-HT2A receptors and large-scale brain networks.
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Affiliation(s)
- Devon Stoliker
- Turner Institute for Brain and Mental Health (D.S., G.F.E., A.R.) and Monash Biomedical Imaging (G.F.E., A.R.), Monash University, Clayton, Victoria, Australia; Wellcome Centre for Human Neuroimaging, UCL, London, United Kingdom (K.J.F., A.R.); and CIFAR Azrieli Global Scholar, CIFAR, Toronto, Canada (A.R.)
| | - Gary F Egan
- Turner Institute for Brain and Mental Health (D.S., G.F.E., A.R.) and Monash Biomedical Imaging (G.F.E., A.R.), Monash University, Clayton, Victoria, Australia; Wellcome Centre for Human Neuroimaging, UCL, London, United Kingdom (K.J.F., A.R.); and CIFAR Azrieli Global Scholar, CIFAR, Toronto, Canada (A.R.)
| | - Karl J Friston
- Turner Institute for Brain and Mental Health (D.S., G.F.E., A.R.) and Monash Biomedical Imaging (G.F.E., A.R.), Monash University, Clayton, Victoria, Australia; Wellcome Centre for Human Neuroimaging, UCL, London, United Kingdom (K.J.F., A.R.); and CIFAR Azrieli Global Scholar, CIFAR, Toronto, Canada (A.R.)
| | - Adeel Razi
- Turner Institute for Brain and Mental Health (D.S., G.F.E., A.R.) and Monash Biomedical Imaging (G.F.E., A.R.), Monash University, Clayton, Victoria, Australia; Wellcome Centre for Human Neuroimaging, UCL, London, United Kingdom (K.J.F., A.R.); and CIFAR Azrieli Global Scholar, CIFAR, Toronto, Canada (A.R.)
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30
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Dourron HM, Strauss C, Hendricks PS. Self-Entropic Broadening Theory: Toward a New Understanding of Self and Behavior Change Informed by Psychedelics and Psychosis. Pharmacol Rev 2022; 74:982-1027. [DOI: 10.1124/pharmrev.121.000514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 06/14/2022] [Accepted: 06/16/2022] [Indexed: 11/22/2022] Open
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31
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Jaster AM, Younkin J, Cuddy T, de la Fuente Revenga M, Poklis JL, Dozmorov MG, González-Maeso J. Differences across sexes on head-twitch behavior and 5-HT 2A receptor signaling in C57BL/6J mice. Neurosci Lett 2022; 788:136836. [PMID: 35963476 PMCID: PMC10114867 DOI: 10.1016/j.neulet.2022.136836] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/27/2022] [Accepted: 08/08/2022] [Indexed: 01/26/2023]
Abstract
Psychedelics, also known as classical hallucinogens, affect processes related to perception, cognition and sensory processing mostly via the serotonin 5-HT2A receptor (5-HT2AR). This class of psychoactive substances, which includes lysergic acid diethylamide (LSD), psilocybin, mescaline and the substituted amphetamine 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), is receiving renewed attention for their potential therapeutic properties as it relates to psychiatric conditions such as depression and substance use disorders. Current studies focused on the potentially clinical effects of psychedelics on human subjects tend to exclude sex as a biological variable. Much of the understanding of psychedelic pharmacology is derived from rodent models, but most of this preclinical research has only focused on male mice. Here we tested the effects of DOI on head-twitch behavior (HTR) - a mouse behavioral proxy of human psychedelic potential - in male and female mice. DOI elicited more HTR in female as compared to male C57BL/6J mice, a sex-specific exacerbated behavior that was not observed in 129S6/SvEv animals. Volinanserin (or M100907) - a 5-HT2AR antagonist - fully prevented DOI-induced HTR in male and female C57BL/6J mice. Accumulation of inositol monophosphate (IP1) in the frontal cortex upon DOI administration showed no sex-related effect in C57BL/6J mice. However, the pharmacokinetic properties of DOI differed among sexes - brain and plasma concentrations of DOI were lower 30 and 60 min after drug administration in female as compared to male C57BL/6J mice. Together, these results suggest strain-dependent and sex-related differences in the behavioral and pharmacokinetic profiles of the 5-HT2AR agonist DOI in C57BL/6J mice, and support the importance of studying sex as a biological variable in preclinical psychedelic research.
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Affiliation(s)
- Alaina M Jaster
- Department of Physiology & Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States; Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States
| | - Jason Younkin
- Department of Physiology & Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States; Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States
| | - Travis Cuddy
- Department of Physiology & Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States
| | - Mario de la Fuente Revenga
- Department of Physiology & Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States; Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States
| | - Justin L Poklis
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States
| | - Mikhail G Dozmorov
- Department of Biostatistics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States
| | - Javier González-Maeso
- Department of Physiology & Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States.
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Kurtz JS, Patel NA, Gendreau JL, Yang C, Brown N, Bui N, Picton B, Harris M, Hatter M, Beyer R, Sahyouni R, Diaz-Aguilar LD, Castellano J, Schuster N, Abraham ME. The Use of Psychedelics in the Treatment of Medical Conditions: An Analysis of Currently Registered Psychedelics Studies in the American Drug Trial Registry. Cureus 2022; 14:e29167. [PMID: 36259015 PMCID: PMC9567237 DOI: 10.7759/cureus.29167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2022] [Indexed: 12/03/2022] Open
Abstract
Although early therapeutic research on psychedelics dates back to the 1940s, this field of investigation was met with many cultural and legal challenges in the 1970s. Over the past two decades, clinical trials using psychedelics have resumed. Therefore, the goal of this study was to (1) better characterize the recent uptrend in psychedelics in clinical trials and (2) identify areas where potentially new clinical trials could be initiated to help in the treatment of widely prevalent medical disorders. A systematic search was conducted on the clinicaltrials.gov database for all registered clinical trials examining the use of psychedelic drugs and was both qualitatively and quantitatively assessed. Analysis of recent studies registered in clinicaltrials.gov was performed using Pearson’s correlation coefficient testing. Statistical analysis and visualization were performed using R software. In totality, 105 clinical trials met this study’s inclusion criteria. The recent uptrend in registered clinical trials studying psychedelics (p = 0.002) was similar to the uptrend in total registered clinical trials in the registry (p < 0.001). All trials took place from 2007 to 2020, with 77.1% of studies starting in 2017 or later. A majority of clinical trials were in phase 1 (53.3%) or phase 2 (25.7%). Common disorders treated include substance addiction, post-traumatic stress disorder, and major depressive disorder. Potential research gaps include studying psychedelics as a potential option for symptomatic treatment during opioid tapering. There appears to be a recent uptrend in registered clinical trials studying psychedelics, which is similar to the recent increase in overall trials registered. Potentially, more studies could be performed to evaluate the potential of psychedelics for symptomatic treatment during opioid tapering and depression refractory to selective serotonin reuptake inhibitors.
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de la Fuente Revenga M, Jaster AM, McGinn J, Silva G, Saha S, González-Maeso J. Tolerance and Cross-Tolerance among Psychedelic and Nonpsychedelic 5-HT 2A Receptor Agonists in Mice. ACS Chem Neurosci 2022; 13:2436-2448. [PMID: 35900876 PMCID: PMC10411500 DOI: 10.1021/acschemneuro.2c00170] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Classical psychedelics represent a subgroup of serotonergic psychoactive substances characterized by their distinct subjective effects on the human psyche. Another unique attribute of this drug class is that such effects become less apparent after repeated exposure within a short time span. The classification of psychedelics as a subgroup within the serotonergic drug family and the tolerance to their effects are replicated by the murine head twitch response (HTR) behavioral paradigm. Here, we aimed to assess tolerance and cross-tolerance to HTR elicited by psychedelic and nonpsychedelic serotonin 2A receptor (5-HT2AR) agonists in mice. We show that repeated (4 days) administration of the psychedelic 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) induced a progressive decrease in HTR behavior. Tolerance to DOI-induced HTR was also observed 24 h after a single administration of this psychedelic. Pretreatment with the 5-HT2AR antagonist M100907 reduced not only the acute manifestation of DOI-induced HTR, but also the development of tolerance to HTR. Additionally, cross-tolerance became apparent between the psychedelics DOI and lysergic acid diethylamide (LSD), whereas repeated administration of the nonpsychedelic 5-HT2AR agonist lisuride did not affect the ability of these two psychedelics to induce HTR. At the molecular level, DOI administration led to down-regulation of 5-HT2AR density in mouse frontal cortex membrane preparations. However, development of tolerance to the effect of DOI on HTR remained unchanged in β-arrestin-2 knockout mice. Together, these data suggest that tolerance to HTR induced by psychedelics involves activation of the 5-HT2AR, is not observable upon repeated administration of nonpsychedelic 5-HT2AR agonists, and occurs via a signaling mechanism independent of β-arrestin-2.
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Affiliation(s)
- Mario de la Fuente Revenga
- Department of Physiology & Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
- Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Alaina M Jaster
- Department of Physiology & Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
| | - John McGinn
- Department of Physiology & Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
| | - Gabriella Silva
- Department of Physiology & Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
| | - Somdatta Saha
- Department of Physiology & Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
| | - Javier González-Maeso
- Department of Physiology & Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
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Abstract
BACKGROUND Postpartum depression (PPD) is a major public health concern and has, at its core, a sense of maternal 'disconnection' - from the self, the infant, and the support system. While PPD bears similarities with MDD, there is increasing evidence for its distinct nature, especially with the unique aspect of the mother-infant relationship. Current treatment modalities for PPD, largely based on those used in major depressive disorder (MDD), have low remission rates with emerging evidence for treatment resistance. It is, therefore, necessary to explore alternative avenues of treatment for PPD. OBJECTIVE In this narrative review, we outline the potential therapeutic rationale for serotonergic psychedelics in the treatment of PPD, and highlight safety and pragmatic considerations for the use of psychedelics in the postpartum period. METHODS We examined the available evidence for the treatment of PPD and the evidence for psychedelics in the treatment of MDD. We explored safety considerations in the use of psychedelics in the postpartum period. RESULTS There is increasing evidence for safety, and encouraging signals for efficacy, of psilocybin in the treatment of MDD. Psilocybin has been shown to catalyse a sense of 'reconnection' in participants with MDD. This effect in PPD, by fostering a sense of 'reconnection' for the mother, may allow for improved mood and maternal sensitivity towards the infant, which can positively impact maternal role gratification and the mother-infant relationship. CONCLUSION Psychedelic assisted therapy in PPD may have a positive effect on the mother-infant dyad and warrants further examination.
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Affiliation(s)
- Chaitra Jairaj
- Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK,The National Maternity Hospital, Dublin, Ireland,Chaitra Jairaj, Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, De Crespigny Park, London SE5 8AF, UK.
| | - James J Rucker
- Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK,Bethlem Royal Hospital, South London and Maudsley National Health Service Foundation Trust, Beckenham, UK
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Golden CT, Chadderton P. Psilocybin reduces low frequency oscillatory power and neuronal phase-locking in the anterior cingulate cortex of awake rodents. Sci Rep 2022; 12:12702. [PMID: 35882885 PMCID: PMC9325720 DOI: 10.1038/s41598-022-16325-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 07/08/2022] [Indexed: 11/18/2022] Open
Abstract
Psilocybin is a hallucinogenic compound that is showing promise in the ability to treat neurological conditions such as depression and post-traumatic stress disorder. There have been several investigations into the neural correlates of psilocybin administration using non-invasive methods, however, there has yet to be an invasive study of the mechanism of action in awake rodents. Using multi-unit extracellular recordings, we recorded local field potential and spiking activity from populations of neurons in the anterior cingulate cortex of awake mice during the administration of psilocybin (2 mg/kg). The power of low frequency bands in the local field potential was found to significantly decrease in response to psilocybin administration, whilst gamma band activity trended towards an increase. The population firing rate was found to increase overall, with just under half of individual neurons showing a significant increase. Psilocybin significantly decreased the level of phase modulation of cells with each neural frequency band except high-gamma oscillations, consistent with a desynchronization of cortical populations. Furthermore, bursting behavior was altered in a subset of cells, with both positive and negative changes in the rate of bursting. Neurons that increased their burst firing following psilocybin administration were highly likely to transition from a phase-modulated to a phase unmodulated state. Taken together, psilocybin reduces low frequency oscillatory power, increases overall firing rates and desynchronizes local neural activity. These findings are consistent with dissolution of the default mode network under psilocybin, and may be indicative of disruption of top-down processing in the acute psychedelic state.
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Affiliation(s)
- Caroline T Golden
- Department of Bioengineering and Centre for Neurotechnology, Imperial College London, London, SW7 2AZ, UK
| | - Paul Chadderton
- School of Physiology Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK.
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van Elk M, Yaden DB. Pharmacological, neural, and psychological mechanisms underlying psychedelics: A critical review. Neurosci Biobehav Rev 2022; 140:104793. [PMID: 35878791 DOI: 10.1016/j.neubiorev.2022.104793] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 07/08/2022] [Accepted: 07/20/2022] [Indexed: 10/17/2022]
Abstract
This paper provides a critical review of several possible mechanisms at different levels of analysis underlying the effects and therapeutic potential of psychedelics. At the (1) biochemical level, psychedelics primarily affect the 5-HT2A receptor, increase neuroplasticity, offer a critical period for social reward learning, and have anti-inflammatory properties. At the (2) neural level, psychedelics have been associated with reduced efficacy of thalamo-cortical filtering, the loosening of top-down predictive signaling and an increased sensitivity to bottom-up prediction errors, and activation of the claustro-cortical-circuit. At the (3) psychological level, psychedelics have been shown to induce altered and affective states, they affect cognition, induce belief change, exert social effects, and can result in lasting changes in behavior. We outline the potential for a unifying account of the mechanisms underlying psychedelics and contrast this with a model of pluralistic causation. Ultimately, a better understanding of the specific mechanisms underlying the effects of psychedelics could allow for a more targeted therapeutic approach. We highlight current challenges for psychedelic research and provide a research agenda to foster insight in the causal-mechanistic pathways underlying the efficacy of psychedelic research and therapy.
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Affiliation(s)
- Michiel van Elk
- Institute of Psychology, Leiden University, Wassenaarseweg 52, 2333 AK Leiden, the Netherlands.
| | - David Bryce Yaden
- The Center for Psychedelic and Consciousness Research, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA
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Dodd S, Norman TR, Eyre HA, Stahl SM, Phillips A, Carvalho AF, Berk M. Psilocybin in neuropsychiatry: a review of its pharmacology, safety, and efficacy. CNS Spectr 2022; 28:1-11. [PMID: 35811423 DOI: 10.1017/s1092852922000888] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Psilocybin is a tryptamine alkaloid found in some mushrooms, especially those of the genus Psilocybe. Psilocybin has four metabolites including the pharmacologically active primary metabolite psilocin, which readily enters the systemic circulation. The psychoactive effects of psilocin are believed to arise due to the partial agonist effects at the 5HT2A receptor. Psilocin also binds to various other receptor subtypes although the actions of psilocin at other receptors are not fully explored. Psilocybin administered at doses sufficient to cause hallucinogenic experiences has been trialed for addictive disorders, anxiety and depression. This review investigates studies of psilocybin and psilocin and assesses the potential for use of psilocybin and a treatment agent in neuropsychiatry. The potential for harm is also assessed, which may limit the use of psilocybin as a pharmacotherapy. Careful evaluation of the number needed to harm vs the number needed to treat will ultimately justify the potential clinical use of psilocybin. This field needs a responsible pathway forward.
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Affiliation(s)
- Seetal Dodd
- IMPACT - The Institute for Mental and Physical Health and Clinical Translation, Deakin University, Geelong, VIC, Australia
- School of Medicine, Deakin University, Geelong, VIC, Australia
- University Hospital Geelong, Barwon Health, Geelong, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC, Australia
- Centre for Youth Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Trevor R Norman
- Department of Psychiatry, The University of Melbourne, Parkville, VIC, Australia
| | - Harris A Eyre
- IMPACT - The Institute for Mental and Physical Health and Clinical Translation, Deakin University, Geelong, VIC, Australia
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Neuroscience-Inspired Policy Initiative, Organisation for Economic Co-Operation and Development (OECD), Meadows Mental Health Policy Institute and the PRODEO Institute, Paris, France
- Global Brain Health Institute, University of California, San Francisco (UCSF), San Francisco, CA, USA
- Global Brain Health Institute, Trinity College Dublin, Dublin, Ireland
- Latin American Brain Health (BrainLat), Universidad Adolfo Ibáñez, Santiago, Chile
- Brain Health Nexus, Cohen Veterans Network, Boston, MA, USA
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA
| | - Stephen M Stahl
- Department of Psychiatry, University of California San Diego, San Diego, CA, USA
| | - Arnie Phillips
- IMPACT - The Institute for Mental and Physical Health and Clinical Translation, Deakin University, Geelong, VIC, Australia
- School of Medicine, Deakin University, Geelong, VIC, Australia
| | - André F Carvalho
- IMPACT - The Institute for Mental and Physical Health and Clinical Translation, Deakin University, Geelong, VIC, Australia
- School of Medicine, Deakin University, Geelong, VIC, Australia
| | - Michael Berk
- IMPACT - The Institute for Mental and Physical Health and Clinical Translation, Deakin University, Geelong, VIC, Australia
- School of Medicine, Deakin University, Geelong, VIC, Australia
- University Hospital Geelong, Barwon Health, Geelong, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC, Australia
- Centre for Youth Mental Health, The University of Melbourne, Parkville, VIC, Australia
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
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Bosch OG, Halm S, Seifritz E. Psychedelics in the treatment of unipolar and bipolar depression. Int J Bipolar Disord 2022; 10:18. [PMID: 35788817 PMCID: PMC9256889 DOI: 10.1186/s40345-022-00265-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 06/09/2022] [Indexed: 11/10/2022] Open
Abstract
This is a narrative review about the role of classic and two atypical psychedelics in the treatment of unipolar and bipolar depression. Since the 1990s, psychedelics experience a renaissance in biomedical research. The so-called classic psychedelics include lysergic acid diethylamide (LSD), psilocybin, mescaline and ayahuasca. Characteristic effects like alterations in sensory perception, as well as emotion- and self-processing are induced by stimulation of serotonin 2A receptors in cortical areas. The new paradigm of psychedelic-assisted psychotherapy suggests a therapeutic framework in which a safely conducted psychedelic experience is integrated into a continuous psychotherapeutic process. First randomized, controlled trials with psilocybin show promising efficacy, tolerability, and adherence in the treatment of unipolar depression. On the other hand, classic psychedelics seem to be associated with the induction of mania, which is an important issue to consider for the design of research and clinical protocols. So called atypical psychedelics are a heterogeneous group with overlapping subjective effects but different neurobiological mechanisms. Two examples of therapeutic value in psychiatry are 3,4-methylenedioxymethamphetamine (MDMA) and ketamine. Since 2020 the ketamine enantiomer esketamine has been granted international approval for treatment-resistant unipolar depression, and also first evidence exists for the therapeutic efficacy of ketamine in bipolar depression. Whether psychedelics will fulfil current expectations and find their way into broader clinical use will depend on future rigorous clinical trials with larger sample sizes. A well-considered therapeutic and legal framework will be crucial for these substances to create new treatment settings and a potential paradigm shift.
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Affiliation(s)
- Oliver G Bosch
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Lenggstrasse 31, PO Box 1931, 8032, Zurich, Switzerland.
| | - Simon Halm
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Lenggstrasse 31, PO Box 1931, 8032, Zurich, Switzerland
| | - Erich Seifritz
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Lenggstrasse 31, PO Box 1931, 8032, Zurich, Switzerland
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Smausz R, Neill J, Gigg J. Neural mechanisms underlying psilocybin's therapeutic potential - the need for preclinical in vivo electrophysiology. J Psychopharmacol 2022; 36:781-793. [PMID: 35638159 PMCID: PMC9247433 DOI: 10.1177/02698811221092508] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Psilocybin is a naturally occurring psychedelic compound with profound perception-, emotion- and cognition-altering properties and great potential for treating brain disorders. However, the neural mechanisms mediating its effects require in-depth investigation as there is still much to learn about how psychedelic drugs produce their profound and long-lasting effects. In this review, we outline the current understanding of the neurophysiology of psilocybin's psychoactive properties, highlighting the need for additional preclinical studies to determine its effect on neural network dynamics. We first describe how psilocybin's effect on brain regions associated with the default-mode network (DMN), particularly the prefrontal cortex and hippocampus, likely plays a key role in mediating its consciousness-altering properties. We then outline the specific receptor and cell types involved and discuss contradictory evidence from neuroimaging studies regarding psilocybin's net effect on activity within these regions. We go on to argue that in vivo electrophysiology is ideally suited to provide a more holistic, neural network analysis approach to understand psilocybin's mode of action. Thus, we integrate information about the neural bases for oscillatory activity generation with the accumulating evidence about psychedelic drug effects on neural synchrony within DMN-associated areas. This approach will help to generate important questions for future preclinical and clinical studies. Answers to these questions are vital for determining the neural mechanisms mediating psilocybin's psychotherapeutic potential, which promises to improve outcomes for patients with severe depression and other difficulty to treat conditions.
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Affiliation(s)
- Rebecca Smausz
- Division of Neuroscience and
Experimental Psychology, Faculty of Biology, Medicine and Health, The
University of Manchester, Manchester, UK
| | - Joanna Neill
- Division of Pharmacy and
Optometry, Faculty of Biology, Medicine and Health, The University of
Manchester, Manchester, UK,Medical Psychedelics Working
Group, Drug Science, UK
| | - John Gigg
- Division of Neuroscience and
Experimental Psychology, Faculty of Biology, Medicine and Health, The
University of Manchester, Manchester, UK,John Gigg, Division of Neuroscience
and Experimental Psychology, Faculty of Biology, Medicine and Health,
The University of Manchester, Manchester, M13 9PT, UK.
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40
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Johnson S, Letheby C. Psychedelic therapy for body dysmorphic disorder. JOURNAL OF PSYCHEDELIC STUDIES 2022. [DOI: 10.1556/2054.2022.00200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
In this opinion piece we propose the investigation of psychedelic-assisted psychotherapy for the treatment of body dysmorphic disorder (BDD). BDD is a psychiatric disorder characterised by appearance-based preoccupations and accompanying compulsions. While safe and effective treatments for BDD exist, non-response and relapse rates remain high. Therefore, there is a need to investigate promising new treatment options for this highly debilitating condition. Preliminary evidence suggests safety, feasibility, and potential efficacy of psychedelic treatments in disorders that share similar psychopathological mechanisms with BDD. Drawing on this evidence, as well as on relevant qualitative reports and theoretical proposals, we argue that it would be worthwhile to conduct a phase 2a study aimed at assessing the safety and feasibility of psychedelic-assisted psychotherapy in BDD. We also offer some suggestions for how future research ought to proceed.
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Affiliation(s)
- Shevaugn Johnson
- College of Education, Psychology, and Social Work, Flinders University, Sturt Road, Bedford Park, South Australia, 5042, Australia
| | - Chris Letheby
- Department of Philosophy, The University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia, 6009, Australia
- Department of Philosophy, The University of Adelaide, North Terrace, Adelaide, South Australia, 5005, Australia
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The psychological processes of classic psychedelics in the treatment of depression: a systematic review protocol. Syst Rev 2022; 11:85. [PMID: 35513876 PMCID: PMC9074259 DOI: 10.1186/s13643-022-01930-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/18/2022] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND There is currently renewed interest in the use of psychedelic therapy in the treatment of psychiatric disorders, including depression. The proposed systematic review will aim to identify, evaluate and summarise the psychological processes of change underlying psychedelic therapy for depression in the current literature and consider the implications these processes may have on the psychotherapy component of treatment. METHODS Scopus, PsycINFO, PubMed and Web of Science databases will be searched using relevant terms. Studies will be included if they discuss the use of a classic psychedelic to treat depression symptomology in an adult population and report or propose psychological processes responsible for depression symptom change. Two authors will independently screen articles, complete quality assessment tools and conduct data extraction. Empirical and non-empirical research will be extracted and synthesised separately. A narrative synthesis approach will be used to report psychological processes identified in the literature. DISCUSSION This systematic review will be the first to collate available evidence on the psychological processes associated with psychedelic therapy for depression. The preliminary nature of this research field is expected to result in the review having several limitations, namely heterogeneity between studies and the inclusion of limited empirical research. We intend for this review to present the current state of the literature, identify gaps and generate candidate variables that warrant further investigation. SYSTEMATIC REVIEW PROSPERO CRD42020197202.
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Avram M, Müller F, Rogg H, Korda A, Andreou C, Holze F, Vizeli P, Ley L, Liechti ME, Borgwardt S. Characterizing thalamocortical (dys)connectivity following d-amphetamine, LSD, and MDMA administration. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2022; 7:885-894. [PMID: 35500840 DOI: 10.1016/j.bpsc.2022.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/28/2022] [Accepted: 04/13/2022] [Indexed: 12/19/2022]
Abstract
BACKGROUND Patients with psychotic disorders present alterations in thalamocortical intrinsic functional connectivity (iFC) as measured by resting-state functional magnetic resonance imaging (rs-fMRI). Specifically, thalamic iFC is increased with sensorimotor cortices (hyperconnectivity) and decreased with prefrontal-limbic cortices (hypoconnectivity). Intriguingly, psychedelics such as lysergic acid diethylamide (LSD) elicit similar thalamocortical-hyperconnectivity with sensorimotor areas in healthy volunteers. It is unclear whether LSD also induces thalamocortical-hypoconnectivity with prefrontal-limbic cortices as current findings are equivocal. Notably, thalamocortical-hyperconnectivity was associated with psychotic symptoms in patients and substance-induced altered states of consciousness in healthy volunteers. Thalamocortical dysconnectivity is likely evoked by altered neurotransmission, e.g., via dopaminergic excess in psychotic disorders and serotonergic agonism in psychedelic-induced states. It is unclear whether thalamocortical dysconnectivity is also elicited by amphetamine-type substances, broadly releasing monoamines (i.e., dopamine, norepinephrine) but producing fewer perceptual effects than psychedelics. METHODS We administrated LSD, d-amphetamine, and 3,4-methylenedioxymethamphetamine (MDMA) in 28 healthy volunteers and investigated their effects on thalamic iFC with two brain networks (auditory-sensorimotor (ASM) and salience (SAL) - corresponding to sensorimotor and prefrontal-limbic cortices, respectively), using a double-blind, placebo-controlled, cross-over design. RESULTS All active substances elicited ASM-thalamic-hyperconnectivity compared to placebo, despite predominantly distinct pharmacological actions and subjective effects. LSD-induced effects correlated with subjective changes in perception, indicating a link between hyperconnectivity and psychedelic-type perceptual alterations. Unlike d-amphetamine and MDMA, which induced hypoconnectivity with SAL, LSD elicited hyperconnectivity. D-amphetamine and MDMA evoked similar thalamocortical dysconnectivity patterns. CONCLUSIONS Psychedelics, empathogens, and psychostimulants evoke thalamocortical-hyperconnectivity with sensorimotor areas, akin to findings in patients with psychotic disorders.
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Affiliation(s)
- Mihai Avram
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, 23538, Germany.
| | - Felix Müller
- Department of Psychiatry (UPK), University of Basel, Basel, 4012, Switzerland
| | - Helena Rogg
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, 23538, Germany
| | - Alexandra Korda
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, 23538, Germany
| | - Christina Andreou
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, 23538, Germany
| | - Friederike Holze
- Division of Clinical Pharmacology and Toxicology, Department of Clinical Research, University Hospital Basel, University of Basel, Basel, 4031, Switzerland
| | - Patrick Vizeli
- Division of Clinical Pharmacology and Toxicology, Department of Clinical Research, University Hospital Basel, University of Basel, Basel, 4031, Switzerland
| | - Laura Ley
- Division of Clinical Pharmacology and Toxicology, Department of Clinical Research, University Hospital Basel, University of Basel, Basel, 4031, Switzerland
| | - Matthias E Liechti
- Division of Clinical Pharmacology and Toxicology, Department of Clinical Research, University Hospital Basel, University of Basel, Basel, 4031, Switzerland
| | - Stefan Borgwardt
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, 23538, Germany
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Girn M, Roseman L, Bernhardt B, Smallwood J, Carhart-Harris R, Nathan Spreng R. Serotonergic psychedelic drugs LSD and psilocybin reduce the hierarchical differentiation of unimodal and transmodal cortex. Neuroimage 2022; 256:119220. [PMID: 35483649 DOI: 10.1016/j.neuroimage.2022.119220] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/03/2022] [Accepted: 04/15/2022] [Indexed: 12/20/2022] Open
Abstract
Lysergic acid diethylamide (LSD) and psilocybin are serotonergic psychedelic compounds with potential in the treatment of mental health disorders. Past neuroimaging investigations have revealed that both compounds can elicit significant changes to whole-brain functional organization and dynamics. A recent proposal linked past findings into a unified model and hypothesized reduced whole-brain hierarchical organization as a key mechanism underlying the psychedelic state, but this has yet to be directly tested. We applied a non-linear dimensionality reduction technique previously used to map hierarchical connectivity gradients to assess cortical organization in the LSD and psilocybin state from two previously published pharmacological resting-state fMRI datasets (N = 15 and 9, respectively). Results supported our primary hypothesis: The principal gradient of cortical connectivity, describing a hierarchy from unimodal to transmodal cortex, was significantly flattened under both drugs relative to their respective placebo conditions. Between-condition contrasts revealed that this was driven by a reduction of functional differentiation at both hierarchical extremes - default and frontoparietal networks at the upper end, and somatomotor at the lower. Gradient-based connectivity mapping indicated that this was underpinned by a disruption of modular unimodal connectivity and increased unimodal-transmodal crosstalk. Results involving the second and third gradient, which, respectively represent axes of sensory and executive differentiation, also showed significant alterations across both drugs. These findings provide support for a recent mechanistic model of the psychedelic state relevant to therapeutic applications of psychedelics. More fundamentally, we provide the first evidence that macroscale connectivity gradients are sensitive to an acute pharmacological manipulation, supporting a role for psychedelics as scientific tools to perturb cortical functional organization.
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Affiliation(s)
- Manesh Girn
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 Rue Université, Montreal, QC H3A 2B4, Canada.
| | - Leor Roseman
- Centre for Psychedelic Research, Department of Brain Sciences, Imperial College London, London, United Kingdom
| | - Boris Bernhardt
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 Rue Université, Montreal, QC H3A 2B4, Canada
| | | | - Robin Carhart-Harris
- Neuroscape Psychedelics Division, Department of Neurology, University of California San Francisco, San Francisco, CA, United States
| | - R Nathan Spreng
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 Rue Université, Montreal, QC H3A 2B4, Canada; Departments of Psychiatry and Psychology, McGill University, Montreal, QC, Canada; Douglas Mental Health University Institute, Verdun, QC, Canada; McConnell Brain Imaging Centre, McGill University, Montreal, QC, Canada
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Doss MK, Madden MB, Gaddis A, Nebel MB, Griffiths RR, Mathur BN, Barrett FS. Models of psychedelic drug action: modulation of cortical-subcortical circuits. Brain 2022; 145:441-456. [PMID: 34897383 PMCID: PMC9014750 DOI: 10.1093/brain/awab406] [Citation(s) in RCA: 51] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 08/10/2021] [Accepted: 10/05/2021] [Indexed: 12/15/2022] Open
Abstract
Classic psychedelic drugs such as psilocybin and lysergic acid diethylamide (LSD) have recaptured the imagination of both science and popular culture, and may have efficacy in treating a wide range of psychiatric disorders. Human and animal studies of psychedelic drug action in the brain have demonstrated the involvement of the serotonin 2A (5-HT2A) receptor and the cerebral cortex in acute psychedelic drug action, but different models have evolved to try to explain the impact of 5-HT2A activation on neural systems. Two prominent models of psychedelic drug action (the cortico-striatal thalamo-cortical, or CSTC, model and relaxed beliefs under psychedelics, or REBUS, model) have emphasized the role of different subcortical structures as crucial in mediating psychedelic drug effects. We describe these models and discuss gaps in knowledge, inconsistencies in the literature and extensions of both models. We then introduce a third circuit-level model involving the claustrum, a thin strip of grey matter between the insula and the external capsule that densely expresses 5-HT2A receptors (the cortico-claustro-cortical, or CCC, model). In this model, we propose that the claustrum entrains canonical cortical network states, and that psychedelic drugs disrupt 5-HT2A-mediated network coupling between the claustrum and the cortex, leading to attenuation of canonical cortical networks during psychedelic drug effects. Together, these three models may explain many phenomena of the psychedelic experience, and using this framework, future research may help to delineate the functional specificity of each circuit to the action of both serotonergic and non-serotonergic hallucinogens.
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Affiliation(s)
- Manoj K Doss
- Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, MD, 21224, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21224, USA
| | - Maxwell B Madden
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Andrew Gaddis
- Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, MD, 21224, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21224, USA
| | - Mary Beth Nebel
- Center for Neurodevelopmental and Imaging Research, Kennedy Krieger Institute, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Roland R Griffiths
- Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, MD, 21224, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21224, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Brian N Mathur
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Frederick S Barrett
- Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, MD, 21224, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21224, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
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45
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Guerrin CGJ, Shoji A, Doorduin J, de Vries EFJ. Immune Activation in Pregnant Rats Affects Brain Glucose Consumption, Anxiety-like Behaviour and Recognition Memory in their Male Offspring. Mol Imaging Biol 2022; 24:740-749. [PMID: 35380336 PMCID: PMC9581871 DOI: 10.1007/s11307-022-01723-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 02/22/2022] [Accepted: 03/21/2022] [Indexed: 11/28/2022]
Abstract
Purpose Prenatal infection during pregnancy is a risk factor for schizophrenia, as well as for other developmental psychiatric disorders, such as autism and bipolar disorder. Schizophrenia patients were reported to have altered brain metabolism and neuroinflammation. However, the link between prenatal infection, altered brain inflammation and metabolism, and schizophrenia remains unclear. In this project, we aimed to evaluate whether there are changes in brain glucose consumption and microglia activation in the offspring of pregnant rats exposed to maternal immune activation (MIA), and if so, whether these changes occur before or after the initiation of schizophrenia-like behaviour. Procedures Pregnant rats were treated with the viral mimic polyinosinic-polycytidylic acid (MIA group) or saline (control group) on gestational day 15. Static PET scans of the male offspring were acquired on postnatal day (PND) 21, 60, and 90, using [11C]-PK11195 and deoxy-2-[18F]fluoro-D-glucose ([18F]-FDG) as tracers to measure TSPO expression in activated microglia and brain glucose consumption, respectively. On PND60 and PND90, anxiety-like behaviour, recognition memory, and sensorimotor gating were measured using the open field test (OFT), novel object recognition test (NOR), and prepulse inhibition test (PPI). Results [18F]-FDG PET demonstrated that MIA offspring displayed higher brain glucose consumption in the whole brain after weaning (p = 0.017), and in the frontal cortex during late adolescence (p = 0.001) and adulthood (p = 0.037) than control rats. [11C]-PK11195 PET did not reveal any changes in TSPO expression in MIA offspring. Prenatal infection induced age-related behavioural alterations. Adolescent MIA offspring displayed a more anxious state in the OFT than controls (p = 0.042). Adult MIA offspring showed recognition memory deficits in the NOR (p = 0.003). Our study did not show any PPI deficits. Conclusions Our results suggest that prenatal immune activation changed neurodevelopment, resulting in increased brain glucose consumption, but not in microglia activation. The increased brain glucose consumption in the frontal cortex of MIA offspring remained until adulthood and was associated with increased anxiety-like behaviour during adolescence and recognition memory deficits in adulthood. Supplementary Information The online version contains supplementary material available at 10.1007/s11307-022-01723-3.
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Affiliation(s)
- Cyprien G J Guerrin
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713, GZ, Groningen, the Netherlands
| | - Alexandre Shoji
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713, GZ, Groningen, the Netherlands
| | - Janine Doorduin
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713, GZ, Groningen, the Netherlands
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713, GZ, Groningen, the Netherlands.
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Psilocybin for Treating Psychiatric Disorders: A Psychonaut Legend or a Promising Therapeutic Perspective? J Xenobiot 2022; 12:41-52. [PMID: 35225956 PMCID: PMC8883979 DOI: 10.3390/jox12010004] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 10/26/2021] [Accepted: 11/24/2021] [Indexed: 11/30/2022] Open
Abstract
Psychedelics extracted from plants have been used in religious, spiritual, and mystic practices for millennia. In 1957, Dr. Hofmann identified and synthesized the prodrug psilocybin, a substance present in more than 200 species of psychedelic mushrooms. Although there were limitations related to the scientific design of many studies, clinical observations performed during the 1950s and 1960s showed a potential therapeutic effect of psilocybin for patients affected by depressive symptoms, anxiety, and conversion disorder. Psilocybin was classed as a schedule I substance in 1970, but the fascination with psychedelics has remained almost unchanged over time, promoting a new scientific interest starting in the 1990s. Recent studies have provided further evidence supporting the suggestive hypothesis of the therapeutic use of psilocybin for treating various psychiatric disorders, including pathological anxiety, mood depressive disorder, and addiction.
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Vollenweider FX, Smallridge JW. Classic Psychedelic Drugs: Update on Biological
Mechanisms. PHARMACOPSYCHIATRY 2022; 55:121-138. [PMID: 35079988 PMCID: PMC9110100 DOI: 10.1055/a-1721-2914] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Renewed interest in the effects of psychedelics in the treatment of psychiatric
disorders warrants a better understanding of the neurobiological mechanisms
underlying the effects of these substances. During the past two decades,
state-of-the-art studies of animals and humans have yielded new important
insights into the molecular, cellular, and systems-level actions of psychedelic
drugs. These efforts have revealed that psychedelics affect primarily
serotonergic receptor subtypes located in cortico-thalamic and cortico-cortical
feedback circuits of information processing. Psychedelic drugs modulate
excitatory-inhibitory balance in these circuits and can participate in
neuroplasticity within brain structures critical for the integration of
information relevant to sensation, cognition, emotions, and the narrative of
self. Neuroimaging studies showed that characteristic dimensions of the
psychedelic experience obtained through subjective questionnaires as well as
alterations in self-referential processing and emotion regulation obtained
through neuropsychological tasks are associated with distinct changes in brain
activity and connectivity patterns at multiple-system levels. These recent
results suggest that changes in self-experience, emotional processing, and
social cognition may contribute to the potential therapeutic effects of
psychedelics.
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Affiliation(s)
- Franz X. Vollenweider
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry,
Psychotherapy and Psychosomatics, University Hospital for Psychiatry Zurich,
Zurich, Switzerland
| | - John W. Smallridge
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry,
Psychotherapy and Psychosomatics, University Hospital for Psychiatry Zurich,
Zurich, Switzerland
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48
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A Research Domain Criteria (RDoC)-Guided Dashboard to Review Psilocybin Target Domains: A Systematic Review. CNS Drugs 2022; 36:1031-1047. [PMID: 36097251 PMCID: PMC9550777 DOI: 10.1007/s40263-022-00944-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/17/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND Preliminary results from randomized controlled studies as well as identified molecular, cellular, and circuit targets of select psychedelics (e.g., psilocybin) suggest that their effects are transdiagnostic. In this review, we exploit the Research Domain Criteria (RDoC) transdiagnostic framework, to synthesize extant literature on psilocybin. OBJECTIVE We aimed to identify RDoC-based effects of psilocybin and vistas for future mechanistic and interventional research. METHODS A systematic search in electronic databases (i.e., PubMed, Scopus, PsycINFO, and Web of Science) performed in January and February 2021 identified English articles published between 1990 and 2020 reporting the effects of psilocybin on mental health measures. Data from included articles were retrieved and organized according to the RDoC bio-behavioral matrix and its constituent six main domains, namely: positive valence systems, negative valence systems, cognitive systems, social processes, sensorimotor systems, and arousal and regulatory systems. RESULTS The preponderance of research with psilocybin has differentially reported beneficial effects on positive valence systems, negative valence system, and social process domains. The data from the included studies support both short-term (23 assessments) and long-term (15 assessments) beneficial effects of psilocybin on the positive valence systems. While 12 of the extracted outcome measures suggest that psilocybin use is associated with increases in the "fear" construct of the negative valence systems domain, 19 findings show no significant effects on this construct, and seven parameters show lowered levels of the "sustained threat" construct in the long term. Thirty-four outcome measures revealed short-term alterations in the social systems' construct namely, "perception and understanding of self," and "social communications" as well as enhancements in "perception and understanding of others" and "affiliation and attachment". The majority of findings related to the cognitive systems' domain reported dyscognitive effects. There have been relatively few studies reporting outcomes of psilocybin on the remaining RDoC domains. Moreover, seven of the included studies suggest the transdiagnostic effects of psilocybin. The dashboard characterization of RDoC outcomes with psilocybin suggests beneficial effects in the measures of reward, threat, and arousal, as well as general social systems. CONCLUSIONS Psilocybin possesses a multi-domain effectiveness. The field would benefit from highly rigorous proof-of-mechanism research to assess the effects of psilocybin using the RDoC framework. The combined effect of psilocybin with psychosocial interventions with RDoC-based outcomes is a priority therapeutic vista.
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49
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Johnson MW. Classic Psychedelics in Addiction Treatment: The Case for Psilocybin in Tobacco Smoking Cessation. Curr Top Behav Neurosci 2022; 56:213-227. [PMID: 35704271 DOI: 10.1007/7854_2022_327] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This manuscript reviews research suggesting that classic psychedelics (5-HT2A receptor agonists) are effective in treating addictions including tobacco use disorder. I review historical research from the 1950s to 1970s suggesting that classic psychedelics are associated with addiction recovery across pharmacologically distinct drugs of addiction. I then review anthropological reports about ceremonial use of classic psychedelics and epidemiological studies that are consistent with anti-addiction efficacy. I review modern research using psilocybin in the treatment of alcohol use disorder and tobacco use disorder. Both lines of research show high success rates in preliminary studies. General anti-addiction efficacy across a variety of classes of addictive drugs is consistent with the notion that the persisting positive behavior change prompted by psychedelic therapy is due to amplification of psychotherapeutic processes. Future research should examine classic psychedelic treatment of additional substance use disorders including for opioids, cocaine, methamphetamine, and cannabis, and other disorders broadly characterized as addictions (e.g., obesity, problem gambling, hypersexual disorder). Future research should also explore addiction treatments with other classic psychedelics including LSD, mescaline, DMT, 5-MeO-DMT, and yet-to-be-discovered compounds. Experimental research is also needed to test different protocols for the delivery of classic psychedelic therapy for addictions. Given the staggering society costs of substance use disorders, including the mortality caused by tobacco smoking, it is critical that public funding be made available for scientists to follow up on promising early findings of classic psychedelics in addiction treatment. The costs and risks of not conducting such research are too great.
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Affiliation(s)
- Matthew W Johnson
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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50
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Kuburi S, Di Passa AM, Tassone VK, Mahmood R, Lalovic A, Ladha KS, Dunlop K, Rizvi S, Demchenko I, Bhat V. Neuroimaging Correlates of Treatment Response with Psychedelics in Major Depressive Disorder: A Systematic Review. CHRONIC STRESS 2022; 6:24705470221115342. [PMID: 35936944 PMCID: PMC9350516 DOI: 10.1177/24705470221115342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/07/2022] [Indexed: 12/03/2022]
Abstract
Preliminary evidence supports the use of psychedelics for major depressive
disorder (MDD). However, less attention has been given to the neural mechanisms
behind their effects. We conducted a systematic review examining the
neuroimaging correlates of antidepressant response following psychedelic
interventions for MDD. Through MEDLINE, Embase, and APA PsycINFO, 187 records
were identified and 42 articles were screened. Six published studies and one
conference abstract were included. Five ongoing trials were included from
subjective outcomesTrials.gov. Our search covered several psychedelics, though
included studies were specific to psilocybin, ayahuasca, and lysergic acid
diethylamide. Three psilocybin studies noted amygdala activity and functional
connectivity (FC) alterations that correlated with treatment response. Two
psilocybin studies reported that FC changes in the medial and ventromedial
prefrontal cortices correlated with treatment response. Two trials from a single
study reported global decreases in brain network modularity which correlated
with antidepressant response. One ayahuasca study reported increased activity in
the limbic regions following treatment. Preliminary evidence suggests that the
default mode and limbic networks may be a target for future research on the
neural mechanisms of psychedelics. More data is required to corroborate these
initial findings as the evidence summarized in this review is based on four
datasets.
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Affiliation(s)
- Sarah Kuburi
- Interventional Psychiatry Program, Mental Health and Addictions Service, St. Michael’s Hospital, 193 Yonge Street 6-013, M5B 1M8, Toronto, Ontario, Canada
| | - Anne-Marie Di Passa
- Interventional Psychiatry Program, Mental Health and Addictions Service, St. Michael’s Hospital, 193 Yonge Street 6-013, M5B 1M8, Toronto, Ontario, Canada
| | - Vanessa K. Tassone
- Interventional Psychiatry Program, Mental Health and Addictions Service, St. Michael’s Hospital, 193 Yonge Street 6-013, M5B 1M8, Toronto, Ontario, Canada
| | - Raesham Mahmood
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Medical Sciences Building, M5S 1A8, Toronto, Ontario, Canada
| | - Aleksandra Lalovic
- Department of Psychiatry, Faculty of Medicine, University of Toronto, 250 College Street, M5T 1R8, Toronto, Ontario, Canada
- Li Ka Shing Knowledge Institute, St. Michael’s Hospital, 209 Victoria Street, M5B 1T8, Toronto, Ontario, Canada
| | - Karim S. Ladha
- Li Ka Shing Knowledge Institute, St. Michael’s Hospital, 209 Victoria Street, M5B 1T8, Toronto, Ontario, Canada
- Department of Anesthesiology and Pain Medicine, University of Toronto, 250 College Street, M5T 1R8, Toronto, Ontario, Canada
- Department of Anesthesia, St. Michael's Hospital, 193 Yonge Street 6-013, M5B 1M8, Toronto, Ontario, Canada
| | - Katharine Dunlop
- Interventional Psychiatry Program, Mental Health and Addictions Service, St. Michael’s Hospital, 193 Yonge Street 6-013, M5B 1M8, Toronto, Ontario, Canada
- Department of Psychiatry, Faculty of Medicine, University of Toronto, 250 College Street, M5T 1R8, Toronto, Ontario, Canada
- Center for Depression and Suicide Studies, St. Michael’s Hospital, Unity Health Toronto, 30 Bond Street, M5B 1W8, Toronto, ON, Canada
- Keenan Research Center for Biomedical Science, St. Michael’s Hospital, Unity Health Toronto, 30 Bond Street, M5B 1W8, Toronto, Ontario, Canada
| | - Sakina Rizvi
- Department of Psychiatry, Faculty of Medicine, University of Toronto, 250 College Street, M5T 1R8, Toronto, Ontario, Canada
- Li Ka Shing Knowledge Institute, St. Michael’s Hospital, 209 Victoria Street, M5B 1T8, Toronto, Ontario, Canada
| | - Ilya Demchenko
- Interventional Psychiatry Program, Mental Health and Addictions Service, St. Michael’s Hospital, 193 Yonge Street 6-013, M5B 1M8, Toronto, Ontario, Canada
| | - Venkat Bhat
- Interventional Psychiatry Program, Mental Health and Addictions Service, St. Michael’s Hospital, 193 Yonge Street 6-013, M5B 1M8, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Medical Sciences Building, M5S 1A8, Toronto, Ontario, Canada
- Department of Psychiatry, Faculty of Medicine, University of Toronto, 250 College Street, M5T 1R8, Toronto, Ontario, Canada
- Li Ka Shing Knowledge Institute, St. Michael’s Hospital, 209 Victoria Street, M5B 1T8, Toronto, Ontario, Canada
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