1
|
Hervig MES, Zühlsdorff K, Olesen SF, Phillips B, Božič T, Dalley JW, Cardinal RN, Alsiö J, Robbins TW. 5-HT 2A and 5-HT 2C receptor antagonism differentially modulate reinforcement learning and cognitive flexibility: behavioural and computational evidence. Psychopharmacology (Berl) 2024:10.1007/s00213-024-06586-w. [PMID: 38594515 DOI: 10.1007/s00213-024-06586-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 03/29/2024] [Indexed: 04/11/2024]
Abstract
RATIONALE Cognitive flexibility, the ability to adapt behaviour in response to a changing environment, is disrupted in several neuropsychiatric disorders, including obsessive-compulsive disorder and major depressive disorder. Evidence suggests that flexibility, which can be operationalised using reversal learning tasks, is modulated by serotonergic transmission. However, how exactly flexible behaviour and associated reinforcement learning (RL) processes are modulated by 5-HT action on specific receptors is unknown. OBJECTIVES We investigated the effects of 5-HT2A receptor (5-HT2AR) and 5-HT2C receptor (5-HT2CR) antagonism on flexibility and underlying RL mechanisms. METHODS Thirty-six male Lister hooded rats were trained on a touchscreen visual discrimination and reversal task. We evaluated the effects of systemic treatments with the 5-HT2AR and 5-HT2CR antagonists M100907 and SB-242084, respectively, on reversal learning and performance on probe trials where correct and incorrect stimuli were presented with a third, probabilistically rewarded, stimulus. Computational models were fitted to task choice data to extract RL parameters, including a novel model designed specifically for this task. RESULTS 5-HT2AR antagonism impaired reversal learning only after an initial perseverative phase, during a period of random choice and then new learning. 5-HT2CR antagonism, on the other hand, impaired learning from positive feedback. RL models further differentiated these effects. 5-HT2AR antagonism decreased punishment learning rate (i.e. negative feedback) at high and low doses. The low dose also decreased reinforcement sensitivity (beta) and increased stimulus and side stickiness (i.e., the tendency to repeat a choice regardless of outcome). 5-HT2CR antagonism also decreased beta, but reduced side stickiness. CONCLUSIONS These data indicate that 5-HT2A and 5-HT2CRs both modulate different aspects of flexibility, with 5-HT2ARs modulating learning from negative feedback as measured using RL parameters and 5-HT2CRs for learning from positive feedback assessed through conventional measures.
Collapse
Affiliation(s)
- Mona El-Sayed Hervig
- Department of Psychology, University of Cambridge, Cambridge, CB2 3EB, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
- Department of Neuroscience, University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Katharina Zühlsdorff
- Department of Psychology, University of Cambridge, Cambridge, CB2 3EB, UK.
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK.
- The Alan Turing Institute, British Library, London, NW1 2DVB, UK.
| | - Sarah F Olesen
- UCL Sainsbury Wellcome Centre for Neural Circuits and Behaviour, London, W1T 4JG, UK
| | - Benjamin Phillips
- Department of Psychology, University of Cambridge, Cambridge, CB2 3EB, UK
| | - Tadej Božič
- UCL Sainsbury Wellcome Centre for Neural Circuits and Behaviour, London, W1T 4JG, UK
| | - Jeffrey W Dalley
- Department of Psychology, University of Cambridge, Cambridge, CB2 3EB, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
- Department of Psychiatry, Herchel Smith Building, Cambridge, CB2 0SZ, UK
| | - Rudolf N Cardinal
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
- Department of Psychiatry, Herchel Smith Building, Cambridge, CB2 0SZ, UK
- Liaison Psychiatry Service, Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge Biomedical Campus, Box 190, Cambridge, CB2 0QQ, UK
| | - Johan Alsiö
- Department of Psychology, University of Cambridge, Cambridge, CB2 3EB, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, BS8 1TD, UK
| | - Trevor W Robbins
- Department of Psychology, University of Cambridge, Cambridge, CB2 3EB, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
| |
Collapse
|
2
|
Luppi AI, Girn M, Rosas FE, Timmermann C, Roseman L, Erritzoe D, Nutt DJ, Stamatakis EA, Spreng RN, Xing L, Huttner WB, Carhart-Harris RL. A role for the serotonin 2A receptor in the expansion and functioning of human transmodal cortex. Brain 2024; 147:56-80. [PMID: 37703310 DOI: 10.1093/brain/awad311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 08/14/2023] [Accepted: 08/18/2023] [Indexed: 09/15/2023] Open
Abstract
Integrating independent but converging lines of research on brain function and neurodevelopment across scales, this article proposes that serotonin 2A receptor (5-HT2AR) signalling is an evolutionary and developmental driver and potent modulator of the macroscale functional organization of the human cerebral cortex. A wealth of evidence indicates that the anatomical and functional organization of the cortex follows a unimodal-to-transmodal gradient. Situated at the apex of this processing hierarchy-where it plays a central role in the integrative processes underpinning complex, human-defining cognition-the transmodal cortex has disproportionately expanded across human development and evolution. Notably, the adult human transmodal cortex is especially rich in 5-HT2AR expression and recent evidence suggests that, during early brain development, 5-HT2AR signalling on neural progenitor cells stimulates their proliferation-a critical process for evolutionarily-relevant cortical expansion. Drawing on multimodal neuroimaging and cross-species investigations, we argue that, by contributing to the expansion of the human cortex and being prevalent at the apex of its hierarchy in the adult brain, 5-HT2AR signalling plays a major role in both human cortical expansion and functioning. Owing to its unique excitatory and downstream cellular effects, neuronal 5-HT2AR agonism promotes neuroplasticity, learning and cognitive and psychological flexibility in a context-(hyper)sensitive manner with therapeutic potential. Overall, we delineate a dual role of 5-HT2ARs in enabling both the expansion and modulation of the human transmodal cortex.
Collapse
Affiliation(s)
- Andrea I Luppi
- Department of Clinical Neurosciences and Division of Anaesthesia, University of Cambridge, Cambridge, CB2 0QQ, UK
- Leverhulme Centre for the Future of Intelligence, University of Cambridge, Cambridge, CB2 1SB, UK
- The Alan Turing Institute, London, NW1 2DB, UK
| | - Manesh Girn
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, H3A 2B4, Canada
- Psychedelics Division-Neuroscape, Department of Neurology, University of California SanFrancisco, San Francisco, CA 94158, USA
| | - Fernando E Rosas
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
- Data Science Institute, Imperial College London, London, SW7 2AZ, UK
- Centre for Complexity Science, Imperial College London, London, SW7 2AZ, UK
| | - Christopher Timmermann
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - Leor Roseman
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - David Erritzoe
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - David J Nutt
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - Emmanuel A Stamatakis
- Department of Clinical Neurosciences and Division of Anaesthesia, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - R Nathan Spreng
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, H3A 2B4, Canada
| | - Lei Xing
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany
| | - Wieland B Huttner
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany
| | - Robin L Carhart-Harris
- Psychedelics Division-Neuroscape, Department of Neurology, University of California SanFrancisco, San Francisco, CA 94158, USA
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| |
Collapse
|
3
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
Affiliation(s)
- Marzena Maćkowiak
- Laboratory of Pharmacology and Brain Biostructure, Pharmacology Department, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
| |
Collapse
|
4
|
Pouyan N, Younesi Sisi F, Kargar A, Scheidegger M, McIntyre RS, Morrow JD. The effects of Lysergic Acid Diethylamide (LSD) on the Positive Valence Systems: A Research Domain Criteria (RDoC)-Informed Systematic Review. CNS Drugs 2023; 37:1027-1063. [PMID: 37999867 PMCID: PMC10703966 DOI: 10.1007/s40263-023-01044-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/16/2023] [Indexed: 11/25/2023]
Abstract
BACKGROUND AND OBJECTIVES The renewed interest in psychedelic research provides growing evidence of potentially unique effects on various aspects of reward processing systems. Using the Research Domain Criteria (RDoC) framework, as proposed by the National Institute of Mental Health, we aim to synthesize the existing literature concerning the impact of lysergic acid diethylamide (LSD) on the RDoC's Positive Valence Systems (PVS) domain, and to identify potential avenues for further research. METHODS Two LSD-related terms (lysergic acid diethylamide and LSD) and 13 PVS-related terms (reward, happiness, bliss, motivation, reinforcement learning, operant, conditioning, satisfaction, decision making, habit, valence, affect, mood) were used to search electronic databases such as PubMed, Scopus, PsychINFO, and Web of Science for relevant articles. A manual search of the reference list resulted in nine additional articles. After screening, articles and data were evaluated and included based on their relevance to the objective of investigating the effects of LSD on the PVS. Articles and data were excluded if they did not provide information about the PVS, were observational in nature, lacked comparators or reference groups, or were duplicates. A risk of bias assessment was performed using the National Toxicology Program's Office of Health Assessment and Translation (NTP OHAT) risk of bias (RoB) tool. Data from the included articles were collected and structured based on the RDoC bio-behavioral matrix, specifically focusing on the PVS domain and its three constituent constructs: reward responsiveness, reward learning, and reward valuation. RESULTS We reviewed 28 clinical studies with 477 participants. Lysergic acid diethylamide, assessed at self-report (23 studies), molecular (5 studies), circuit (4 studies), and paradigm (3 studies) levels, exhibited dose-dependent mood improvement (20 short-term and 3 long-term studies). The subjective and neural effects of LSD were linked to the 5-HT2A receptor (molecular). Animal studies (14 studies) suggested LSD could mildly reinforce conditioned place preference without aversion and reduce responsiveness to other rewards. Findings on reward learning were inconsistent but hinted at potential associative learning enhancements. Reward valuation measures indicated potential reductions in effort expenditure for other reinforcers. CONCLUSION Our findings are consistent with our previous work, which indicated classical psychedelics, primarily serotonin 2A receptor agonists, enhanced reward responsiveness in healthy individuals and patient populations. Lysergic acid diethylamide exhibits a unique profile in the reward learning and valuation constructs. Using the RDoC-based framework, we identified areas for future research, enhancing our understanding of the impact of LSD on reward processing. However, applying RDoC to psychedelic research faces limitations due to diverse study designs that were not initially RDoC-oriented. Limitations include subjective outcome measure selection aligned with RDoC constructs and potential bias in synthesizing varied studies. Additionally, some human studies were open-label, introducing potential bias compared to randomized, blinded studies.
Collapse
Affiliation(s)
- Niloufar Pouyan
- Michigan Psychedelic Center (M-PsyC), and Chronic Pain and Fatigue Research Center (CPFRC), University of Michigan Medical School, Ann Arbor, MI, USA.
- Neuroscience Graduate Program, and Program in Biomedical Sciences (PIBS), University of Michigan Medical School, 1135 Catherine Street, Box 5619, 2960 Taubman Health Science Library, Ann Arbor, MI, USA.
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Zurich, Switzerland.
- Aracell Zist Darou pharmaceutical, Tehran, Iran.
| | - Farnaz Younesi Sisi
- Yaadmaan Institute for Brain, Cognition and Memory Studies, Tehran, Iran
- Cognitive Neurology and Neuropsychiatry Research Center, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Alireza Kargar
- Cognitive Neurology and Neuropsychiatry Research Center, Tehran University of Medical Sciences (TUMS), Tehran, Iran
- Department of Clinical Pharmacy, School of pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - 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
| | - Roger S McIntyre
- Mood Disorders Psychopharmacology Unit (MDPU), University Health Network, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Jonathan D Morrow
- Neuroscience Graduate Program, and Program in Biomedical Sciences (PIBS), University of Michigan Medical School, 1135 Catherine Street, Box 5619, 2960 Taubman Health Science Library, Ann Arbor, MI, USA
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
5
|
Ekins TG, Brooks I, Kailasa S, Rybicki-Kler C, Jedrasiak-Cape I, Donoho E, Mashour GA, Rech J, Ahmed OJ. Cellular rules underlying psychedelic control of prefrontal pyramidal neurons. bioRxiv 2023:2023.10.20.563334. [PMID: 37961554 PMCID: PMC10634703 DOI: 10.1101/2023.10.20.563334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Classical psychedelic drugs are thought to increase excitability of pyramidal cells in prefrontal cortex via activation of serotonin 2A receptors (5-HT2ARs). Here, we instead find that multiple classes of psychedelics dose-dependently suppress intrinsic excitability of pyramidal neurons, and that extracellular delivery of psychedelics decreases excitability significantly more than intracellular delivery. A previously unknown mechanism underlies this psychedelic drug action: enhancement of ubiquitously expressed potassium "M-current" channels that is independent of 5-HT2R activation. Using machine-learning-based data assimilation models, we show that M-current activation interacts with previously described mechanisms to dramatically reduce intrinsic excitability and shorten working memory timespan. Thus, psychedelic drugs suppress intrinsic excitability by modulating ion channels that are expressed throughout the brain, potentially triggering homeostatic adjustments that can contribute to widespread therapeutic benefits.
Collapse
Affiliation(s)
- Tyler G Ekins
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, MI 48109
| | - Isla Brooks
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
| | - Sameer Kailasa
- Dept. of Mathematics, University of Michigan, Ann Arbor, MI 48109
| | - Chloe Rybicki-Kler
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109
| | | | - Ethan Donoho
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
| | - George A. Mashour
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, MI 48109
| | - Jason Rech
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Omar J Ahmed
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, MI 48109
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109
| |
Collapse
|
6
|
Salinsky LM, Merritt CR, Zamora JC, Giacomini JL, Anastasio NC, Cunningham KA. μ-opioid receptor agonists and psychedelics: pharmacological opportunities and challenges. Front Pharmacol 2023; 14:1239159. [PMID: 37886127 PMCID: PMC10598667 DOI: 10.3389/fphar.2023.1239159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 09/28/2023] [Indexed: 10/28/2023] Open
Abstract
Opioid misuse and opioid-involved overdose deaths are a massive public health problem involving the intertwined misuse of prescription opioids for pain management with the emergence of extremely potent fentanyl derivatives, sold as standalone products or adulterants in counterfeit prescription opioids or heroin. The incidence of repeated opioid overdose events indicates a problematic use pattern consistent with the development of the medical condition of opioid use disorder (OUD). Prescription and illicit opioids reduce pain perception by activating µ-opioid receptors (MOR) localized to the central nervous system (CNS). Dysregulation of meso-corticolimbic circuitry that subserves reward and adaptive behaviors is fundamentally involved in the progressive behavioral changes that promote and are consequent to OUD. Although opioid-induced analgesia and the rewarding effects of abused opioids are primarily mediated through MOR activation, serotonin (5-HT) is an important contributor to the pharmacology of opioid abused drugs (including heroin and prescription opioids) and OUD. There is a recent resurgence of interest into psychedelic compounds that act primarily through the 5-HT2A receptor (5-HT 2A R) as a new frontier in combatting such diseases (e.g., depression, anxiety, and substance use disorders). Emerging data suggest that the MOR and 5-HT2AR crosstalk at the cellular level and within key nodes of OUD circuitry, highlighting a major opportunity for novel pharmacological intervention for OUD. There is an important gap in the preclinical profiling of psychedelic 5-HT2AR agonists in OUD models. Further, as these molecules carry risks, additional analyses of the profiles of non-hallucinogenic 5-HT2AR agonists and/or 5-HT2AR positive allosteric modulators may provide a new pathway for 5-HT2AR therapeutics. In this review, we discuss the opportunities and challenges associated with utilizing 5-HT2AR agonists as therapeutics for OUD.
Collapse
Affiliation(s)
| | | | | | | | - Noelle C. Anastasio
- Center for Addiction Sciences and Therapeutics and Department of Pharmacology and Toxicology, John Sealy School of Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Kathryn A. Cunningham
- Center for Addiction Sciences and Therapeutics and Department of Pharmacology and Toxicology, John Sealy School of Medicine, University of Texas Medical Branch, Galveston, TX, United States
| |
Collapse
|
7
|
Mishra B, Tarai S, Ratre V, Bit A. Processing of attentional and emotional stimuli depends on retrospective response of foot pressure: Conceptualizing neuron-cognitive distribution in human brain. Comput Biol Med 2023; 164:107186. [PMID: 37480678 DOI: 10.1016/j.compbiomed.2023.107186] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/08/2023] [Accepted: 06/13/2023] [Indexed: 07/24/2023]
Abstract
Cognitive function of human brain requires temporal execution of emotional or attentional tasks, or their inter-dependence influences. Smooth execution of such tasks requires spontaneous distribution of cognitive load at specific regions of brain based on its classification. A strong connectivity between peripheral sensors and central nervous system is thought to assist the cognitive load distribution effectively. Novelty of current study evaluates the modulation of foot pressure and its mapping with distributed cognitive load while executing attentional biased emotional tasks. Emotional stimulus in form of happy and sad faces with attentional paradigm drawn on them were used in the study. Behavioral results were measured with respect to the analysis of response time (RT) and response accuracy (%). Neurological signals were acquired using 10-channel EEG data acquisition system, whereas, another 6 channels were used to measure foot pressure in the left and right feet at three different locations of foot. Acquired signals were further analyzed in time and frequency domains to interpret the cognitive load distribution, and the influence of foot pressure on distribution of cognitive loads. We found that the foot pressure accelerated the response accuracy rate in attending the local scope of attention, which was not in the case of global scope of attention. This means that the global attention does not require any pressure from peripheral sensory neurons. Our event related potential (ERP) results revealed that the early sensory negative N100 characterized the processing of global scope of attention coupled with high-foot pressure. However, the late positive peak of P300 and P600 associated with local scope of attention along with high-foot pressure. The global scope of attention with low-foot pressure modulates delta and theta oscillations. These results largely contribute to the literature on cognitive neuroscience of attention and it corelation with the peripheral sensory foot pressure.
Collapse
Affiliation(s)
- Bharti Mishra
- Department of Biomedical Engineering, National Institute of Technology, Raipur, India
| | - Shashikanta Tarai
- Department of Humanities and Social Sciences, National Institute of Technology, Raipur, India
| | - Vinod Ratre
- Department of Biomedical Engineering, National Institute of Technology, Raipur, India
| | - Arindam Bit
- Department of Biomedical Engineering, National Institute of Technology, Raipur, India.
| |
Collapse
|
8
|
Abstract
In recent years, psychedelic-assisted psychotherapies have reentered the realm of rigorous scientific inquiry, garnering much attention from both the psychiatric community and the broader public. Headlines on major media platforms frequently tout the psychedelic future of psychiatry, and patients increasingly ask about the prospect of using psychedelics during their sessions. Despite this enthusiasm, psychedelics remain in an investigational stage, and more research and regulatory work are required before psychedelics can be deemed appropriate for general clinical use. In this climate, psychiatrists are increasingly curious about the prospects of psychedelic treatments. This review's goal was to help psychiatrists better understand the complexities of the burgeoning field of psychedelic-assisted psychotherapy. The discussion encompasses issues surrounding psychedelics in their current investigational stage and issues for psychiatrists to consider should psychedelics become available for broad clinical use. This review discusses research equipoise in the context of the current enthusiasm for psychedelics, informed consent, patient vulnerability, equity and access, differences between clinical and nonclinical psychedelic uses, and psychedelic self-enhancement. As psychedelics move closer toward regulatory approval beyond research settings, it is vital that these promising treatments be used ethically. The unique features of psychedelic therapies, including the altered states of consciousness they produce and the vulnerability that such states entail for patients, require careful consideration to minimize potential ethical pitfalls. This review seeks to ensure that psychiatrists are equipped to use psychedelic psychotherapy both ethically and effectively.
Collapse
Affiliation(s)
- Gregory S Barber
- Private practice, Bethesda (Barber); Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut (Dike)
| | - Charles C Dike
- Private practice, Bethesda (Barber); Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut (Dike)
| |
Collapse
|
9
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
10
|
Weiss B, Wingert A, Erritzoe D, Campbell WK. Prevalence and therapeutic impact of adverse life event reexperiencing under ceremonial ayahuasca. Sci Rep 2023; 13:9438. [PMID: 37296197 PMCID: PMC10256717 DOI: 10.1038/s41598-023-36184-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
The present study examined the safety and efficacy of the ceremonial use of ayahuasca in relation to reports of heightened life event reexperiencing under psychedelics. The study examined (1) the prevalence of specific types of adverse life event reexperiencing, (2) characteristics predictive of reexperiencing, (3) the psychological character of reexperiencing, and (4) the impact of reexperiencing on mental health. Participants were recruited from three ayahuasca healing and spiritual centers in South and Central America (N = 33 military veterans, 306 non-veterans) using self-report data at three timepoints (Pre-retreat, Post-retreat, 3-months post-retreat). Reexperiencing adverse life events under ayahuasca was common, with women showing particularly high probability of reexperiencing sexual assault, veterans reexperiencing combat-related trauma, and individuals with a self-reported lifetime diagnosis of post-traumatic stress disorder exhibiting a substantively higher prevalence of reexperiencing. Reexperiencing was associated with states of cognitive reappraisal, psychological flexibility, and discomfort during ceremonies, and participants who reexperienced adverse life events exhibited greater reductions in trait neuroticism following their ceremonies. Clinical implications of these results for the application of psychedelics to mood and stress disorders are discussed.
Collapse
Affiliation(s)
- Brandon Weiss
- Division of Psychiatry, Imperial College London, London, UK.
| | | | - David Erritzoe
- Division of Psychiatry, Imperial College London, London, UK
| | | |
Collapse
|
11
|
Abstract
Anecdotal evidence has indicated that psychedelic substances may acutely enhance creative task performance, although empirical support for this claim is mixed at best. Clinical research has shown that psychedelics might have enduring effects on mood and well-being. However, there is no neurocognitive framework that ties acute changes in cognition to long-term effects in mood. In this review, we operationalize creativity within an emerging cognitive control framework and assess the current empirical evidence of the effects of psychedelics on creativity. Next, we leverage insights about the mechanisms and computations by which other psychoactive drugs act to enhance versus impair cognition, in particular to those that act on catecholamines, the neurophysiological consequences of which are relatively well understood. Finally, we use the same framework to link the suggested psychedelic-induced improvements in creativity with enduring psychedelic-induced improvements in mood.
Collapse
Affiliation(s)
- Ceyda Sayalı
- Center for Psychedelic and Consciousness Research, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
| | - Frederick S Barrett
- Center for Psychedelic and Consciousness Research, 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 21224, USA; Department of Psychological & Brain Sciences, Krieger School of Arts & Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
| |
Collapse
|
12
|
Roberts BF, Zylko AL, Waters CE, Crowder JD, Gibbons WJ, Sen AK, Jones JA, McMurray MS. Effect of psilocybin on decision-making and motivation in the healthy rat. Behav Brain Res 2023; 440:114262. [PMID: 36529299 DOI: 10.1016/j.bbr.2022.114262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/02/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
Psilocybin and its active metabolite psilocin are hallucinogenic serotonergic agonists with high affinity for several serotonin receptors. In addition to underlying the hallucinogenic effects of these compounds, serotonin receptor activation also has important effects on decision-making and goal-directed behaviors. The impact of psilocybin and psilocin on these cognitive systems, however, remains unclear. This study investigated the effects of psilocybin treatment on decision-making and motivation in healthy male and female rats. We compared probability and delay discounting performance of psilocybin treated (1 mg/kg) to vehicle rats (n = 10/sex/group), and further assessed motivation in each group using a progressive ratio task. We also confirmed drug action by assessing head twitch responses after psilocybin treatment (1 mg/kg). Results from this study demonstrated that exposure to 1 mg/kg psilocybin did not affect decision-making in the probability and delay discounting tasks and did not reduce response rates in the progressive ratio task. However, psilocybin treatment did cause the expected increase in head twitch responses in both male and female rats, demonstrating that the drug was delivered at a pharmacologically relevant dosage. Combined, these results suggest that psilocybin may not impair or improve decision-making and motivation. Considering recent interest in psilocybin as a potential fast-acting therapeutic for a variety of mental health disorders, our findings also suggest the therapeutic effects of this drug may not be mediated by changes to the brain systems underlying reward and decision-making. Finally, these results may have important implications regarding the relative safety of this compound, suggesting that widespread cognitive impairments may not be seen in subjects, even after chronic treatment.
Collapse
Affiliation(s)
| | - Alexia L Zylko
- Miami University, Department of Psychology, Oxford, OH 45056, USA
| | | | | | - William J Gibbons
- Miami University, Department of Chemical, Paper, and Biomedical Engineering, Oxford, OH 45056, USA
| | - Abhishek K Sen
- Miami University, Department of Chemical, Paper, and Biomedical Engineering, Oxford, OH 45056, USA
| | - J Andrew Jones
- Miami University, Department of Chemical, Paper, and Biomedical Engineering, Oxford, OH 45056, USA; PsyBio Therapeutics, Inc., Oxford, OH 45056, USA
| | | |
Collapse
|
13
|
Torrado Pacheco A, Olson RJ, Garza G, Moghaddam B. Acute psilocybin enhances cognitive flexibility in rats. Neuropsychopharmacology 2023; 48:1011-1020. [PMID: 36807609 PMCID: PMC10209151 DOI: 10.1038/s41386-023-01545-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 02/22/2023]
Abstract
Psilocybin has been shown to improve symptoms of depression and anxiety when combined with psychotherapy or other clinician-guided interventions. To understand the neural basis for this pattern of clinical efficacy, experimental and conceptual approaches that are different than traditional laboratory models of anxiety and depression are needed. A potential novel mechanism is that acute psilocybin improves cognitive flexibility, which then enhances the impact of clinician-assisted interventions. Consistent with this idea, we find that acute psilocybin robustly improves cognitive flexibility in male and female rats using a task where animals switched between previously learned strategies in response to uncued changes in the environment. Psilocybin did not influence Pavlovian reversal learning, suggesting that its cognitive effects are selective to enhanced switching between previously learned behavioral strategies. The serotonin (5HT) 2 A receptor antagonist ketanserin blocked psilocybin's effect on set-shifting, while a 5HT2C-selective antagonist did not. Ketanserin alone also improved set-shifting performance, suggesting a complex relationship between psilocybin's pharmacology and its impact on flexibility. Further, the psychedelic drug 2,5-Dimethoxy-4-iodoamphetamine (DOI) impaired cognitive flexibility in the same task, suggesting that this effect of psilocybin does not generalize to all other serotonergic psychedelics. We conclude that the acute impact of psilocybin on cognitive flexibility provides a useful behavioral model to investigate its neuronal effects relevant to its positive clinical outcome.
Collapse
Affiliation(s)
- Alejandro Torrado Pacheco
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, 97239, USA.
| | - Randall J Olson
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Gabriela Garza
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, 97239, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Bita Moghaddam
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, 97239, USA.
| |
Collapse
|
14
|
Torrado Pacheco A, Olson RJ, Garza G, Moghaddam B. Acute psilocybin enhances cognitive flexibility in rats. bioRxiv 2023:2023.01.09.523291. [PMID: 36712091 PMCID: PMC9881983 DOI: 10.1101/2023.01.09.523291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Psilocybin has been shown to improve symptoms of depression and anxiety when combined with psychotherapy or other clinician-guided interventions. To understand the neural basis for this pattern of clinical efficacy, experimental and conceptual approaches that are different than traditional laboratory models of anxiety and depression are needed. A potential novel mechanism is that acute psilocybin improves cognitive flexibility, which then enhances the impact of clinician-assisted interventions. Consistent with this idea, we find that acute psilocybin robustly improves cognitive flexibility in male and female rats using a task where animals switched between previously learned strategies in response to uncued changes in the environment. Psilocybin did not influence Pavlovian reversal learning, suggesting that its cognitive effects are selective to enhanced switching between previously learned behavioral strategies. The serotonin (5HT) 2A receptor antagonist ketanserin blocked psilocybin's effect on set-shifting, while a 5HT2C-selective antagonist did not. Ketanserin alone also improved set-shifting performance, suggesting a complex relationship between psilocybin's pharmacology and its impact on flexibility. Further, the psychedelic drug 2,5-Dimethoxy-4-iodoamphetamine (DOI) impaired cognitive flexibility in the same task, suggesting that this effect of psilocybin does not generalize to all other serotonergic psychedelics. We conclude that the acute impact of psilocybin on cognitive flexibility provides a useful behavioral model to investigate its neuronal effects relevant to its positive clinical outcome.
Collapse
Affiliation(s)
- Alejandro Torrado Pacheco
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239,Corresponding author:;
| | - Randall J. Olson
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239
| | - Gabriela Garza
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239,Current address: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109
| | - Bita Moghaddam
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239,Corresponding author:;
| |
Collapse
|
15
|
Kanen JW, Luo Q, Rostami Kandroodi M, Cardinal RN, Robbins TW, Nutt DJ, Carhart-Harris RL, den Ouden HEM. Effect of lysergic acid diethylamide (LSD) on reinforcement learning in humans. Psychol Med 2022; 53:1-12. [PMID: 36411719 PMCID: PMC10600934 DOI: 10.1017/s0033291722002963] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 08/28/2022] [Accepted: 08/31/2022] [Indexed: 11/23/2022]
Abstract
BACKGROUND The non-selective serotonin 2A (5-HT2A) receptor agonist lysergic acid diethylamide (LSD) holds promise as a treatment for some psychiatric disorders. Psychedelic drugs such as LSD have been suggested to have therapeutic actions through their effects on learning. The behavioural effects of LSD in humans, however, remain incompletely understood. Here we examined how LSD affects probabilistic reversal learning (PRL) in healthy humans. METHODS Healthy volunteers received intravenous LSD (75 μg in 10 mL saline) or placebo (10 mL saline) in a within-subjects design and completed a PRL task. Participants had to learn through trial and error which of three stimuli was rewarded most of the time, and these contingencies switched in a reversal phase. Computational models of reinforcement learning (RL) were fitted to the behavioural data to assess how LSD affected the updating ('learning rates') and deployment of value representations ('reinforcement sensitivity') during choice, as well as 'stimulus stickiness' (choice repetition irrespective of reinforcement history). RESULTS Raw data measures assessing sensitivity to immediate feedback ('win-stay' and 'lose-shift' probabilities) were unaffected, whereas LSD increased the impact of the strength of initial learning on perseveration. Computational modelling revealed that the most pronounced effect of LSD was the enhancement of the reward learning rate. The punishment learning rate was also elevated. Stimulus stickiness was decreased by LSD, reflecting heightened exploration. Reinforcement sensitivity differed by phase. CONCLUSIONS Increased RL rates suggest LSD induced a state of heightened plasticity. These results indicate a potential mechanism through which revision of maladaptive associations could occur in the clinical application of LSD.
Collapse
Affiliation(s)
- Jonathan W. Kanen
- Department of Psychology, University of Cambridge, Cambridge, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Qiang Luo
- National Clinical Research Center for Aging and Medicine at Huashan Hospital, State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science and Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, 200433, China
- Center for Computational Psychiatry, Ministry of Education-Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence, Human Phenome Institute, Fudan University, Shanghai, 200032, China
- Shanghai Key Laboratory of Mental Health and Psychological Crisis Intervention, School of Psychology and Cognitive Science, East China Normal University, Shanghai, 200241, China
| | - Mojtaba Rostami Kandroodi
- Department of Cognitive Science and Artificial Intelligence, Tilburg University, Tilburg, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Rudolf N. Cardinal
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Department of Psychiatry, University of Cambridge, Cambridge, UK
- Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK
| | - Trevor W. Robbins
- Department of Psychology, University of Cambridge, Cambridge, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - David J. Nutt
- Department of Brain Sciences, Centre for Psychedelic Research, Imperial College London, London, UK
| | - Robin L. Carhart-Harris
- Neuroscape Psychedelics Division, University of California San Francisco, San Francisco, California, USA
| | - Hanneke E. M. den Ouden
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| |
Collapse
|
16
|
Gaddis A, Lidstone DE, Nebel MB, Griffiths RR, Mostofsky SH, Mejia AF, Barrett FS. Psilocybin induces spatially constrained alterations in thalamic functional organizaton and connectivity. Neuroimage 2022; 260:119434. [PMID: 35792293 DOI: 10.1016/j.neuroimage.2022.119434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/15/2022] [Accepted: 06/30/2022] [Indexed: 10/17/2022] Open
Abstract
BACKGROUND Classic psychedelics, such as psilocybin and LSD, and other serotonin 2A receptor (5-HT2AR) agonists evoke acute alterations in perception and cognition. Altered thalamocortical connectivity has been hypothesized to underlie these effects, which is supported by some functional MRI (fMRI) studies. These studies have treated the thalamus as a unitary structure, despite known differential 5-HT2AR expression and functional specificity of different intrathalamic nuclei. Independent Component Analysis (ICA) has been previously used to identify reliable group-level functional subdivisions of the thalamus from resting-state fMRI (rsfMRI) data. We build on these efforts with a novel data-maximizing ICA-based approach to examine psilocybin-induced changes in intrathalamic functional organization and thalamocortical connectivity in individual participants. METHODS Baseline rsfMRI data (n=38) from healthy individuals with a long-term meditation practice was utilized to generate a statistical template of thalamic functional subdivisions. This template was then applied in a novel ICA-based analysis of the acute effects of psilocybin on intra- and extra-thalamic functional organization and connectivity in follow-up scans from a subset of the same individuals (n=18). We examined correlations with subjective reports of drug effect and compared with a previously reported analytic approach (treating the thalamus as a single functional unit). RESULTS Several intrathalamic components showed significant psilocybin-induced alterations in spatial organization, with effects of psilocybin largely localized to the mediodorsal and pulvinar nuclei. The magnitude of changes in individual participants correlated with reported subjective effects. These components demonstrated predominant decreases in thalamocortical connectivity, largely with visual and default mode networks. Analysis in which the thalamus is treated as a singular unitary structure showed an overall numerical increase in thalamocortical connectivity, consistent with previous literature using this approach, but this increase did not reach statistical significance. CONCLUSIONS We utilized a novel analytic approach to discover psilocybin-induced changes in intra- and extra-thalamic functional organization and connectivity of intrathalamic nuclei and cortical networks known to express the 5-HT2AR. These changes were not observed using whole-thalamus analyses, suggesting that psilocybin may cause widespread but modest increases in thalamocortical connectivity that are offset by strong focal decreases in functionally relevant intrathalamic nuclei.
Collapse
Affiliation(s)
- Andrew Gaddis
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Daniel E Lidstone
- Center for Neurodevelopmental and Imaging Research, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, 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 21205, USA
| | - Roland R Griffiths
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Stewart H Mostofsky
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Neurodevelopmental and Imaging Research, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Amanda F Mejia
- Department of Statistics, Indiana University Bloomington, Bloomington, IN 47408, USA
| | - Frederick S Barrett
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA.
| |
Collapse
|
17
|
Odland AU, Kristensen JL, Andreasen JT. Animal Behavior in Psychedelic Research. Pharmacol Rev 2022; 74:1176-1205. [PMID: 36180111 DOI: 10.1124/pharmrev.122.000590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/30/2022] [Indexed: 11/22/2022] Open
Abstract
Psychedelic-assisted psychotherapy holds great promise in the treatment of mental health disorders. Research into 5-hydroxytryptamine 2A receptor (5-HT2AR) agonist psychedelic compounds has increased dramatically over the past two decades. In humans, these compounds produce drastic effects on consciousness, and their therapeutic potential relates to changes in the processing of emotional, social, and self-referential information. The use of animal behavior to study psychedelics is under debate, and this review provides a critical perspective on the translational value of animal behavior studies in psychedelic research. Acute activation of 5-HT2ARs produces head twitches and unique discriminative cues, disrupts sensorimotor gating, and stimulates motor activity while inhibiting exploration in rodents. The acute treatment with psychedelics shows discrepant results in conventional rodent tests of depression-like behaviors but generally induces anxiolytic-like effects and inhibits repetitive behavior in rodents. Psychedelics impair waiting impulsivity but show discrepant effects in other tests of cognitive function. Tests of social interaction also show conflicting results. Effects on measures of time perception depend on the experimental schedule. Lasting or delayed effects of psychedelics in rodent tests related to different behavioral domains appear to be rather sensitive to changes in experimental protocols. Studying the effects of psychedelics on animal behaviors of relevance to effects on psychiatric symptoms in humans, assessing lasting effects, publishing negative findings, and relating behaviors in rodents and humans to other more translatable readouts, such as neuroplastic changes, will improve the translational value of animal behavioral studies in psychedelic research. SIGNIFICANCE STATEMENT: Psychedelics like LSD and psilocybin have received immense interest as potential new treatments of psychiatric disorders. Psychedelics change high-order consciousness in humans, and there is debate about the use of animal behavior studies to investigate these compounds. This review provides an overview of the behavioral effects of 5-HT2AR agonist psychedelics in laboratory animals and discusses the translatability of the effects in animals to effects in humans. Possible ways to improve the utility of animal behavior in psychedelic research are discussed.
Collapse
Affiliation(s)
- Anna U Odland
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Jesper L Kristensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Jesper T Andreasen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
| |
Collapse
|
18
|
Yang KH, Han BH, Palamar JJ. Past-year hallucinogen use in relation to psychological distress, depression, and suicidality among US adults. Addict Behav 2022; 132:107343. [PMID: 35525189 PMCID: PMC9177770 DOI: 10.1016/j.addbeh.2022.107343] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/15/2022] [Accepted: 04/26/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND There is renewed interest in the clinical application of hallucinogenic substances to treat a range of psychiatric conditions. However, there is mixed evidence regarding how use of such substances outside of medical settings relates to psychological distress, depression, and suicidality. METHODS We examined data from a US representative sample of noninstitutionalized adults from the 2015-2020 National Survey on Drug Use and Health (N = 241,675). We evaluated whether past-year use of specific hallucinogens (i.e., LSD, DMT/AMT/Foxy, salvia divinorum, ecstasy [MDMA/Molly], ketamine) is associated with reporting past-year serious psychological distress (SPD), major depressive episode (MDE), and suicidality. Generalized linear models using Poisson and log link were used to estimate adjusted prevalence ratios (aPRs), controlling for sociodemographic characteristics and past-year use of various other illegal drugs. RESULTS LSD use was associated with an increased likelihood of MDE (aPR = 1.23, 95% CI: 1.10-1.37) and suicidal thinking (aPR = 1.21, 95% CI: 1.09-1.34). Similar associations were observed between salvia divinorum use and suicidal thinking (aPR = 1.41, 95% CI: 1.00-1.97) and between DMT/AMT/Foxy use and suicidal planning (aPR = 1.81 95% CI: 1.17-2.81). On the other hand, ecstasy use was associated with a decreased likelihood of SPD (aPR = 0.83, 95% CI: 0.77-0.89), MDE (aPR = 0.91, 95% CI: 0.83-1.00), and suicidal thinking (aPR = 0.86, 95% CI: 0.75-0.99). CONCLUSION Findings suggest there are differences among specific hallucinogens with respect to depression and suicidality. More research is warranted to understand consequences of and risk factors for hallucinogen use outside of medical settings among adults experiencing depression or suicidality.
Collapse
Affiliation(s)
- Kevin H Yang
- University of California San Diego Department of Medicine, Division of Geriatrics, Gerontology and Palliative Care, 9500 Gilman Drive, San Diego, CA 92093, USA.
| | - Benjamin H Han
- University of California San Diego Department of Medicine, Division of Geriatrics, Gerontology and Palliative Care, 9500 Gilman Drive, San Diego, CA 92093, USA.
| | - Joseph J Palamar
- New York University Grossman School of Medicine, Department of Population Health, 180 Madison Avenue, New York, NY 10016, USA.
| |
Collapse
|
19
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
20
|
Ornelas IM, Cini FA, Wießner I, Marcos E, de Araújo D, Goto-Silva L, Nascimento J, Silva SRB, Costa MN, Falchi M, Olivieri R, Palhano-Fontes F, Sequerra E, Martins-de-Souza D, Feilding A, Rennó-Costa C, Tófoli LF, Rehen SK, Ribeiro S. Nootropic effects of LSD: Behavioral, molecular and computational evidence. Exp Neurol 2022; 356:114148. [PMID: 35732217 DOI: 10.1016/j.expneurol.2022.114148] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 06/03/2022] [Accepted: 06/14/2022] [Indexed: 11/26/2022]
Abstract
The therapeutic use of classical psychedelic substances such as d-lysergic acid diethylamide (LSD) surged in recent years. Studies in rodents suggest that these effects are produced by increased neural plasticity, including stimulation of the mTOR pathway, a key regulator of metabolism, plasticity, and aging. Could psychedelic-induced neural plasticity be harnessed to enhance cognition? Here we show that LSD treatment enhanced performance in a novel object recognition task in rats, and in a visuo-spatial memory task in humans. A proteomic analysis of human brain organoids showed that LSD affected metabolic pathways associated with neural plasticity, including mTOR. To gain insight into the relation of neural plasticity, aging and LSD-induced cognitive gains, we emulated the experiments in rats and humans with a neural network model of a cortico-hippocampal circuit. Using the baseline strength of plasticity as a proxy for age and assuming an increase in plasticity strength related to LSD dose, the simulations provided a good fit for the experimental data. Altogether, the results suggest that LSD has nootropic effects.
Collapse
Affiliation(s)
- Isis M Ornelas
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
| | - Felipe A Cini
- Brain Institute, Federal University of Rio Grande do Norte (UFRN), Natal, Brazil
| | - Isabel Wießner
- Brain Institute, Federal University of Rio Grande do Norte (UFRN), Natal, Brazil; Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Encarni Marcos
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, San Juan de Alicante, Spain
| | - Dráulio de Araújo
- Brain Institute, Federal University of Rio Grande do Norte (UFRN), Natal, Brazil
| | - Livia Goto-Silva
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
| | - Juliana Nascimento
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil; Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Sergio R B Silva
- Brain Institute, Federal University of Rio Grande do Norte (UFRN), Natal, Brazil
| | - Marcelo N Costa
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil; Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Marcelo Falchi
- Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Rodolfo Olivieri
- Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | | | - Eduardo Sequerra
- Brain Institute, Federal University of Rio Grande do Norte (UFRN), Natal, Brazil
| | - Daniel Martins-de-Souza
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil; Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil; Instituto Nacional de Biomarcadores em Neuropsiquiatria (INBION), Conselho Nacional de Desenvolvimento Científico e Tecnológico, São Paulo, Brazil; Experimental Medicine Research Cluster (EMRC), University of Campinas, Campinas, Brazil
| | | | - César Rennó-Costa
- Digital Metropolis Institute, Federal University of Rio Grande do Norte (UFRN), Natal, Brazil.
| | - Luis Fernando Tófoli
- Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil.
| | - Stevens K Rehen
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil; Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.
| | - Sidarta Ribeiro
- Brain Institute, Federal University of Rio Grande do Norte (UFRN), Natal, Brazil.
| |
Collapse
|
21
|
Müller CP. Serotonin and Consciousness-A Reappraisal. Behav Brain Res 2022; 432:113970. [PMID: 35716774 DOI: 10.1016/j.bbr.2022.113970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/01/2022] [Accepted: 06/06/2022] [Indexed: 11/02/2022]
Abstract
The serotonergic system of the brain is a major modulator of behaviour. Here we describe a re-appraisal of its function for consciousness based on anatomical, functional and pharmacological data. For a better understanding, the current model of consciousness is expanded. Two parallel streams of conscious flow are distinguished. A flow of conscious content and an affective consciousness flow. While conscious content flow has its functional equivalent in the activity of higher cortico-cortical and cortico-thalamic networks, affective conscious flow originates in segregated deeper brain structures for single emotions. It is hypothesized that single emotional networks converge on serotonergic and other modulatory transmitter neurons in the brainstem where a bound percept of an affective conscious flow is formed. This is then dispersed to cortical and thalamic networks, where it is time locked with conscious content flow at the level of these networks. Serotonin acts in concert with other modulatory systems of the brain stem with some possible specialization on single emotions. Together, these systems signal a bound percept of affective conscious flow. Dysfunctions in the serotonergic system may not only give rise to behavioural and somatic symptoms, but also essentially affect the coupling of conscious affective flow with conscious content flow, leading to the affect-stained subjective side of mental disorders like anxiety, depression, or schizophrenia. The present model is an attempt to integrate the growing insights into serotonergic system function. However, it is acknowledged, that several key claims are still at a heuristic level that need further empirical support.
Collapse
Affiliation(s)
- Christian P Müller
- Department of Psychiatry and Psychotherapy, University Clinic, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany; Centre for Drug Research, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
| |
Collapse
|
22
|
Wießner I, Falchi M, Palhano-Fontes F, Oliveira Maia L, Feilding A, Ribeiro S, Bezerra Mota N, Araujo DB, Tófoli LF. Low-dose LSD and the stream of thought: Increased Discontinuity of Mind, Deep Thoughts and abstract flow. Psychopharmacology (Berl) 2022; 239:1721-1733. [PMID: 34708255 DOI: 10.1007/s00213-021-06006-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/07/2021] [Indexed: 01/28/2023]
Abstract
RATIONALE Stream of thought describes the nature of the mind when it is freely roaming, a mental state that is continuous and highly dynamic as in mind-wandering or free association. Classic serotonergic psychedelics are known to profoundly impact perception, cognition and language, yet their influence on the stream of thought remains largely unexplored. OBJECTIVE To elucidate the effects of LSD on the stream of thought. METHODS In a randomized, double-blind, placebo-controlled, crossover study, 24 healthy participants received 50 μg lysergic acid diethylamide (LSD) or inactive placebo. Mind-wandering was measured by the Amsterdam Resting State Questionnaire (ARSQ), free association by the Forward Flow Task (FFT) for three seed word types (animals, objects, abstract words). ARSQ and FFT were assessed at +0 h, +2 h, +4 h, +6 h, +8 h and +24 h after drug administration, respectively. RESULTS LSD, compared to placebo, induced different facets of mind-wandering we conceptualized as "chaos" (Discontinuity of Mind, decreased Sleepiness, Planning, Thoughts under Control, Thoughts about Work and Thoughts about Past), "meaning" (Deep Thoughts, Not Sharing Thoughts) and "sensation" (Thoughts about Odours, Thoughts about Sounds). LSD increased the FFT for abstract words reflecting an "abstract flow" under free association. Overall, chaos was strongest pronounced (+2 h to +6 h), followed by meaning (+2 h to +4 h), sensation (+2 h) and abstract flow (+4 h). CONCLUSIONS LSD affects the stream of thought within several levels (active, passive), facets (chaos, meaning, sensation, abstractness) and time points (from +2 h to +6 h). Increased chaos, meaning and abstract flow at +4 h indicate the utility of a late therapeutic window in psycholytic therapy.
Collapse
Affiliation(s)
- Isabel Wießner
- Department of Medical Psychology and Psychiatry, School of Medical Sciences, University of Campinas, Rua Tessália Vieira de Camargo 126, Cidade Universitária Zeferino Vaz, Campinas, São Paulo, 13083-887, 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, Rua Tessália Vieira de Camargo 126, Cidade Universitária Zeferino Vaz, Campinas, São Paulo, 13083-887, 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
| | - Lucas Oliveira Maia
- Department of Medical Psychology and Psychiatry, School of Medical Sciences, University of Campinas, Rua Tessália Vieira de Camargo 126, Cidade Universitária Zeferino Vaz, Campinas, São Paulo, 13083-887, Brazil.,Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
| | | | - Sidarta Ribeiro
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Natália Bezerra Mota
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.,Department of Physics, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | - Draulio B Araujo
- 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, Rua Tessália Vieira de Camargo 126, Cidade Universitária Zeferino Vaz, Campinas, São Paulo, 13083-887, Brazil.,Interdisciplinary Cooperation for Ayahuasca Research and Outreach (ICARO), School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil
| |
Collapse
|
23
|
Abstract
Renewed interest in psychedelics has reignited the debate about whether and how they change human beliefs. In both the clinical and social-cognitive domains, psychedelic consumption may be accompanied by profound, and sometimes lasting, belief changes. We review these changes and their possible underlying mechanisms. Rather than inducing de novo beliefs, we argue psychedelics may instead change the impact of affect and of others' suggestions on how beliefs are imputed. Critically, we find that baseline beliefs (in the possible effects of psychedelics, for example) might color the acute effects of psychedelics as well as longer-term changes. If we are to harness the apparent potential of psychedelics in the clinic and for human flourishing more generally, these possibilities must be addressed empirically.
Collapse
Affiliation(s)
- H T McGovern
- School of Psychology, The University of Queensland, Brisbane, QLD, Australia
| | - P Leptourgos
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - B T Hutchinson
- Research School of Psychology, The Australian National University, Canberra, ACT, Australia
| | - P R Corlett
- Department of Psychiatry, Yale University, New Haven, CT, USA.
| |
Collapse
|
24
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
25
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
26
|
Tagliazucchi E. Language as a Window Into the Altered State of Consciousness Elicited by Psychedelic Drugs. Front Pharmacol 2022; 13:812227. [PMID: 35392561 PMCID: PMC8980225 DOI: 10.3389/fphar.2022.812227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/01/2022] [Indexed: 11/22/2022] Open
Abstract
Psychedelics are drugs capable of eliciting profound alterations in the subjective experience of the users, sometimes with long-lasting consequences. Because of this, psychedelic research tends to focus on human subjects, given their capacity to construct detailed narratives about the contents of their consciousness experiences. In spite of its relevance, the interaction between serotonergic psychedelics and language production is comparatively understudied in the recent literature. This review is focused on two aspects of this interaction: how the acute effects of psychedelic drugs impact on speech organization regardless of its semantic content, and how to characterize the subjective effects of psychedelic drugs by analyzing the semantic content of written retrospective reports. We show that the computational characterization of language production is capable of partially predicting the therapeutic outcome of individual experiences, relate the effects elicited by psychedelics with those associated with other altered states of consciousness, draw comparisons between the psychedelic state and the symptomatology of certain psychiatric disorders, and investigate the neurochemical profile and mechanism of action of different psychedelic drugs. We conclude that researchers studying psychedelics can considerably expand the range of their potential scientific conclusions by analyzing brief interviews obtained before, during and after the acute effects. Finally, we list a series of questions and open problems that should be addressed to further consolidate this approach.
Collapse
Affiliation(s)
- Enzo Tagliazucchi
- Latin American Brain Health Institute (BrainLat), Universidad Adolfo Ibanez, Santiago, Chile.,Departamento de Física, Universidad de Buenos Aires and Instituto de Física de Buenos Aires (IFIBA, CONICET), Pabellón I, Ciudad Universitaria (1428), Buenos Aires, Argentina
| |
Collapse
|
27
|
Abstract
Substance use disorders (SUD) represent a significant public health issue with a high need for novel and efficacious treatment options. In light of this high unmet need, recent results reporting beneficial outcomes of psychedelic-assisted therapy in SUD are particularly relevant. However, several questions remain with regard to this treatment approach. The clinical mechanisms of action of psychedelic substances in the treatment of SUD are not well understood. Closing this knowledge gap is critical to inform and optimize the psychotherapeutic embedding of the acute substance administration. In this chapter, we discuss potential mechanisms that have implications on psychotherapeutic approaches including induced neuroplasticity, alterations in brain network connectivity, reward and emotion processing, social connectedness, insight, and mystical experiences. Furthermore, we outline considerations and approaches that leverage these mechanisms in order to optimize the therapeutic embedding by maximizing synergy between substance effects and psychotherapy. Understanding the mechanisms of action, developing psychotherapeutic approaches accordingly, and evaluating their synergistic efficacy in scientific studies will be critical to advance the framework of psychedelic-assisted therapy for addiction, create evidence-based approaches, and achieve the best treatment outcome for patients with SUD.
Collapse
Affiliation(s)
- Nathalie M Rieser
- Pharmaco-Neuroimaging and Cognitive-Emotional Processing, Department of Psychiatry, Psychotherapy and Psychosomatics, University of Zurich, Psychiatric University Hospital Zurich, Zurich, Switzerland.
| | - Marcus Herdener
- Center for Addictive Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics, University of Zurich, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Katrin H Preller
- Pharmaco-Neuroimaging and Cognitive-Emotional Processing, Department of Psychiatry, Psychotherapy and Psychosomatics, University of Zurich, Psychiatric University Hospital Zurich, Zurich, Switzerland
| |
Collapse
|
28
|
van den Berg M, Magaraggia I, Schreiber R, Hillhouse TM, Porter JH. How to account for hallucinations in the interpretation of the antidepressant effects of psychedelics: a translational framework. Psychopharmacology (Berl) 2022; 239:1853-1879. [PMID: 35348806 PMCID: PMC9166823 DOI: 10.1007/s00213-022-06106-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/24/2022] [Indexed: 01/02/2023]
Abstract
RATIONALE Recent trials with psychedelics in major depressive disorder and treatment-resistant depression showed remarkable improvements in depressive symptoms that can last for up to several months after even a single administration. The lack of an appropriate placebo control group-as patients are often able to discriminate the subjective effects of the drug-and an incomplete understanding of the role of the hallucinogenic and mystical experience, hampers the interpretation of these therapeutic effects. OBJECTIVES To control for these factors, we developed a translational framework based on establishing pharmacokinetic/pharmacodynamic (PK/PD) relationships in rodents and humans for hallucinogenic (i.e., discriminative stimulus effects in rodents and humans; head twitch responses in rodents; questionnaires in humans) and therapeutic effects. For the latter, we selected the pattern separation and attentional set-shifting tasks as measures for cognitive flexibility because of their high translational value. We predict that these PK/PD analyses will lead to a more objective evaluation of improvements in patients compared to relying only on the currently used self-reported questionnaires. We hypothesize that-if the role of the hallucinogenic experience is not central in the antidepressant effects of psychedelics-the ED50's for the therapeutic effects will be significantly lower than for the hallucinogenic and mystical effects. CONCLUSION Our framework will help to inform future studies that aim at the elucidation of the mechanism(s) of action of psychedelics in depression, and the role of the acute subjective and/or hallucinogenic experience in their effects.
Collapse
Affiliation(s)
- Manon van den Berg
- Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands ,Faculty of Psychology and Neuroscience, Section Neuropsychology & Psychopharmacology, Maastricht University, Maastricht, The Netherlands
| | - Igor Magaraggia
- Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands ,Faculty of Psychology and Neuroscience, Section Neuropsychology & Psychopharmacology, Maastricht University, Maastricht, The Netherlands
| | - Rudy Schreiber
- Faculty of Psychology and Neuroscience, Section Neuropsychology & Psychopharmacology, Maastricht University, Maastricht, The Netherlands.
| | - Todd M. Hillhouse
- Department of Psychology, University of Wisconsin Green Bay, Green Bay, WI USA
| | - Joseph H. Porter
- Department of Psychology, Virginia Commonwealth University, Richmond, USA
| |
Collapse
|
29
|
Kelly JR, Gillan CM, Prenderville J, Kelly C, Harkin A, Clarke G, O'Keane V. Psychedelic Therapy's Transdiagnostic Effects: A Research Domain Criteria (RDoC) Perspective. Front Psychiatry 2021; 12:800072. [PMID: 34975593 PMCID: PMC8718877 DOI: 10.3389/fpsyt.2021.800072] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 11/19/2021] [Indexed: 12/12/2022] Open
Abstract
Accumulating clinical evidence shows that psychedelic therapy, by synergistically combining psychopharmacology and psychological support, offers a promising transdiagnostic treatment strategy for a range of disorders with restricted and/or maladaptive habitual patterns of emotion, cognition and behavior, notably, depression (MDD), treatment resistant depression (TRD) and addiction disorders, but perhaps also anxiety disorders, obsessive-compulsive disorder (OCD), Post-Traumatic Stress Disorder (PTSD) and eating disorders. Despite the emergent transdiagnostic evidence, the specific clinical dimensions that psychedelics are efficacious for, and associated underlying neurobiological pathways, remain to be well-characterized. To this end, this review focuses on pre-clinical and clinical evidence of the acute and sustained therapeutic potential of psychedelic therapy in the context of a transdiagnostic dimensional systems framework. Focusing on the Research Domain Criteria (RDoC) as a template, we will describe the multimodal mechanisms underlying the transdiagnostic therapeutic effects of psychedelic therapy, traversing molecular, cellular and network levels. These levels will be mapped to the RDoC constructs of negative and positive valence systems, arousal regulation, social processing, cognitive and sensorimotor systems. In summarizing this literature and framing it transdiagnostically, we hope we can assist the field in moving toward a mechanistic understanding of how psychedelics work for patients and eventually toward a precise-personalized psychedelic therapy paradigm.
Collapse
Affiliation(s)
- John R. Kelly
- Department of Psychiatry, Trinity College, Dublin, Ireland
- Department of Psychiatry, Tallaght University Hospital, Dublin, Ireland
| | - Claire M. Gillan
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
- School of Psychology, Trinity College, Dublin, Ireland
- Global Brain Health Institute, Trinity College, Dublin, Ireland
| | - Jack Prenderville
- Transpharmation Ireland Ltd, Institute of Neuroscience, Trinity College, Dublin, Ireland
- Discipline of Physiology, School of Medicine, Trinity College, Dublin, Ireland
| | - Clare Kelly
- Department of Psychiatry, Trinity College, Dublin, Ireland
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
- School of Psychology, Trinity College, Dublin, Ireland
| | - Andrew Harkin
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
- School of Pharmacy and Pharmaceutical Sciences, Trinity College, Dublin, Ireland
| | - Gerard Clarke
- Department of Psychiatry and Neurobehavioral Science, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Veronica O'Keane
- Department of Psychiatry, Trinity College, Dublin, Ireland
- Department of Psychiatry, Tallaght University Hospital, Dublin, Ireland
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
| |
Collapse
|
30
|
Doss MK, Považan M, Rosenberg MD, Sepeda ND, Davis AK, Finan PH, Smith GS, Pekar JJ, Barker PB, Griffiths RR, Barrett FS. Psilocybin therapy increases cognitive and neural flexibility in patients with major depressive disorder. Transl Psychiatry 2021; 11:574. [PMID: 34750350 DOI: 10.1038/s41398-021-01706-y] [Citation(s) in RCA: 95] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 10/14/2021] [Accepted: 10/26/2021] [Indexed: 12/19/2022] Open
Abstract
Psilocybin has shown promise for the treatment of mood disorders, which are often accompanied by cognitive dysfunction including cognitive rigidity. Recent studies have proposed neuropsychoplastogenic effects as mechanisms underlying the enduring therapeutic effects of psilocybin. In an open-label study of 24 patients with major depressive disorder, we tested the enduring effects of psilocybin therapy on cognitive flexibility (perseverative errors on a set-shifting task), neural flexibility (dynamics of functional connectivity or dFC via functional magnetic resonance imaging), and neurometabolite concentrations (via magnetic resonance spectroscopy) in brain regions supporting cognitive flexibility and implicated in acute psilocybin effects (e.g., the anterior cingulate cortex, or ACC). Psilocybin therapy increased cognitive flexibility for at least 4 weeks post-treatment, though these improvements were not correlated with the previously reported antidepressant effects. One week after psilocybin therapy, glutamate and N-acetylaspartate concentrations were decreased in the ACC, and dFC was increased between the ACC and the posterior cingulate cortex (PCC). Surprisingly, greater increases in dFC between the ACC and PCC were associated with less improvement in cognitive flexibility after psilocybin therapy. Connectome-based predictive modeling demonstrated that baseline dFC emanating from the ACC predicted improvements in cognitive flexibility. In these models, greater baseline dFC was associated with better baseline cognitive flexibility but less improvement in cognitive flexibility. These findings suggest a nuanced relationship between cognitive and neural flexibility. Whereas some enduring increases in neural dynamics may allow for shifting out of a maladaptively rigid state, larger persisting increases in neural dynamics may be of less benefit to psilocybin therapy.
Collapse
|
31
|
Garcia-Romeu A, Darcy S, Jackson H, White T, Rosenberg P. Psychedelics as Novel Therapeutics in Alzheimer's Disease: Rationale and Potential Mechanisms. Curr Top Behav Neurosci 2021; 56:287-317. [PMID: 34734390 DOI: 10.1007/7854_2021_267] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Serotonin 2A receptor (5-HT2AR) agonist "classic psychedelics" are drawing increasing interest as potential mental health treatments. Recent work suggests psychedelics can exert persisting anxiolytic and antidepressant effects lasting up to several months after a single administration. Data indicate acute subjective drug effects as important psychological factors involved in observed therapeutic benefits. Additionally, animal models have shown an important role for 5-HT2AR agonists in modulating learning and memory function with relevance for Alzheimer's Disease (AD) and related dementias. A number of biological mechanisms of action are under investigation to elucidate 5-HT2AR agonists' therapeutic potential, including enhanced neuroplasticity, anti-inflammatory effects, and alterations in brain functional connectivity. These diverse lines of research are reviewed here along with a discussion of AD pathophysiology and neuropsychiatric symptoms to highlight classic psychedelics as potential novel pharmacotherapies for patients with AD. Human clinical research suggests a possible role for high-dose psychedelic administration in symptomatic treatment of depressed mood and anxiety in early-stage AD. Preclinical data indicate a potential for low- or high-dose psychedelic treatment regimens to slow or reverse brain atrophy, enhance cognitive function, and slow progression of AD. In conclusion, rationale and potential approaches for preliminary research with psychedelics in patients with AD are presented, and ramifications of this line of investigation for development of novel AD treatments are discussed.
Collapse
Affiliation(s)
- Albert Garcia-Romeu
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Sean Darcy
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hillary Jackson
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Toni White
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Memory and Alzheimer's Treatment Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Paul Rosenberg
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Memory and Alzheimer's Treatment Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|
32
|
Basedow LA, Riemer TG, Reiche S, Kreutz R, Majić T. Neuropsychological Functioning in Users of Serotonergic Psychedelics - A Systematic Review and Meta-Analysis. Front Pharmacol 2021; 12:739966. [PMID: 34603053 PMCID: PMC8481924 DOI: 10.3389/fphar.2021.739966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/01/2021] [Indexed: 12/20/2022] Open
Abstract
Background: Serotonergic psychedelics (SPs) like LSD, psilocybin, DMT, and mescaline are a heterogeneous group of substances that share agonism at 5-HT2a receptors. Besides the ability of these substances to facilitate profoundly altered states of consciousness, persisting psychological effects have been reported after single administrations, which outlast the acute psychedelic effects. In this review and meta-analysis, we investigated if repeated SP use associates with a characteristic neuropsychological profile indicating persisting effects on neuropsychological function. Methods: We conducted a systematic review of studies investigating the neuropsychological performance in SP users, searching studies in Medline, Web of Science, embase, ClinicalTrials.gov, and EudraCT. Studies were included if they reported at least one neuropsychological measurement in users of SPs. Studies comparing SP users and non-users that reported mean scores and standard deviations were included in an exploratory meta-analysis. Results: 13 studies (N = 539) published between 1969 and 2020 were included in this systematic review. Overall, we found that only three SPs were specifically investigated: ayahuasca (6 studies, n = 343), LSD (5 studies, n = 135), and peyote (1 study, n = 61). However, heterogeneity of the methodological quality was high across studies, with matching problems representing the most important limitation. Across all SPs, no uniform pattern of neuropsychological impairment was identified. Rather, the individual SPs seemed to be associated with distinct neuropsychological profiles. For instance, one study (n = 42) found LSD users to perform worse in trials A and B of the Trail-Making task, whereas meta-analytic assessment (5 studies, n = 352) of eleven individual neuropsychological measures indicated a better performance of ayahuasca users in the Stroop incongruent task (p = 0.03) and no differences in the others (all p > 0.05). Conclusion: The majority of the included studies were not completely successful in controlling for confounders such as differences in non-psychedelic substance use between SP-users and non-users. Our analysis suggests that LSD, ayahuasca and peyote may have different neuropsychological consequences associated with their use. While LSD users showed reduced executive functioning and peyote users showed no differences across domains, there is some evidence that ayahuasca use is associated with increased executive functioning.
Collapse
Affiliation(s)
- Lukas A. Basedow
- Department of Child and Adolescent Psychiatry, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Thomas G. Riemer
- Institute of Clinical Pharmacology and Toxicology, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charité–Universitätsmedizin Berlin, Berlin, Germany
- Department of Psychiatry and Psychotherapy, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Simon Reiche
- Department of Psychiatry and Psychotherapy, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Reinhold Kreutz
- Institute of Clinical Pharmacology and Toxicology, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Tomislav Majić
- Department of Psychiatry and Psychotherapy, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charité–Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
33
|
Abstract
Psychedelic 5-hydroxytryptamine 2A receptor (5-HT2AR) agonists are showing promise in the treatment of psychiatric disorders, such as treatment-resistant depression and anxiety. Human studies suggest that enhanced cognitive flexibility may contribute to their clinical efficacy. Both improvement and impairment of cognitive flexibility has been reported with 5-HT2AR ligands, making the link between 5-HT2AR pharmacology and cognitive flexibility equivocal. We tested the selective 5-HT2AR agonist 25CN-NBOH in healthy male C57BL/6JOlaHsd mice in a touchscreen-based mouse reversal learning test. No effects were observed on acquisition of the new stimulus-reward contingency, learning errors, or perseverative responses during reversal. Our results suggest that 25CN-NBOH does not affect reversal learning in the schedule used in this study.
Collapse
Affiliation(s)
- Anna U Odland
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | | | | |
Collapse
|
34
|
Zeifman R, Singhal N, Breslow L, Weissman CR. On the Relationship between Classic Psychedelics and Suicidality: A Systematic Review. ACS Pharmacol Transl Sci 2021; 4:436-451. [PMID: 33860173 PMCID: PMC8033757 DOI: 10.1021/acsptsci.1c00024] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Indexed: 12/13/2022]
Abstract
Use of classic psychedelics (e.g., psilocybin, ayahuasca, and lysergic acid diethylamide) is increasing, and psychedelic therapy is receiving growing attention as a novel mental health intervention. Suicidality remains a potential safety concern associated with classic psychedelics and is, concurrently, a mental health concern that psychedelic therapy may show promise in targeting. Accordingly, further understanding of the relationship between classic psychedelics and suicidality is needed. Therefore, we conducted a systematic review of the relationship between classic psychedelics (both non-clinical psychedelic use and psychedelic therapy) and suicidality. We identified a total of 64 articles, including 41 articles on the association between non-clinical classic psychedelic use and suicidality and 23 articles on the effects of psychedelic therapy on suicidality. Findings on the association between lifetime classic psychedelic use and suicidality were mixed, with studies finding positive, negative, and no significant association. A small number of reports of suicide and decreased suicidality following non-clinical classic psychedelic use were identified. Several cases of suicide in early psychedelic therapy were identified; however, it was unclear whether this was due to psychedelic therapy itself. In recent psychedelic therapy clinical trials, we found no reports of increased suicidality and preliminary evidence for acute and sustained decreases in suicidality following treatment. We identify some remaining questions and provide suggestions for future research on the association between classic psychedelics and suicidality.
Collapse
Affiliation(s)
- Richard
J. Zeifman
- Department
of Psychology, Ryerson University, Toronto, Ontario M5B 2K3, Canada
| | - Nikhita Singhal
- Department
of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada
| | - Leah Breslow
- Independent
Researcher, Toronto, Ontario, Canada
| | - Cory R. Weissman
- Department
of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada
| |
Collapse
|
35
|
Mason NL, Kuypers KPC, Reckweg JT, Müller F, Tse DHY, Da Rios B, Toennes SW, Stiers P, Feilding A, Ramaekers JG. Spontaneous and deliberate creative cognition during and after psilocybin exposure. Transl Psychiatry 2021; 11:209. [PMID: 33833225 DOI: 10.1038/s41398-021-01335-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 03/18/2021] [Accepted: 03/29/2021] [Indexed: 02/02/2023] Open
Abstract
Creativity is an essential cognitive ability linked to all areas of our everyday functioning. Thus, finding a way to enhance it is of broad interest. A large number of anecdotal reports suggest that the consumption of psychedelic drugs can enhance creative thinking; however, scientific evidence is lacking. Following a double-blind, placebo-controlled, parallel-group design, we demonstrated that psilocybin (0.17 mg/kg) induced a time- and construct-related differentiation of effects on creative thinking. Acutely, psilocybin increased ratings of (spontaneous) creative insights, while decreasing (deliberate) task-based creativity. Seven days after psilocybin, number of novel ideas increased. Furthermore, we utilized an ultrahigh field multimodal brain imaging approach, and found that acute and persisting effects were predicted by within- and between-network connectivity of the default mode network. Findings add some support to historical claims that psychedelics can influence aspects of the creative process, potentially indicating them as a tool to investigate creativity and subsequent underlying neural mechanisms. Trial NL6007; psilocybin as a tool for enhanced cognitive flexibility; https://www.trialregister.nl/trial/6007 .
Collapse
|
36
|
Abstract
RATIONALE Memory plays a central role in the psychedelic experience. The spontaneous recall and immersive reliving of autobiographical memories has frequently been noted by researchers and clinicians as a salient phenomenon in the profile of subjective effects of classic psychedelic drugs such as psilocybin, LSD, and ayahuasca. The ability for psychedelics to provoke vivid memories has been considered important to their clinical efficacy. OBJECTIVE This review aims to examine and aggregate the findings from experimental, observational, and qualitative studies on the acute modulation of memory by classic psychedelics in humans. METHOD A literature search was conducted using PubMed and PsycInfo as well as manual review of references from eligible studies. Publications reporting quantitative and/or qualitative findings were included; animal studies and case reports were excluded. RESULTS Classic psychedelics produce dose-dependently increasing impairments in memory task performance, such that low doses produce no impairment and higher doses produce increasing levels of impairment. This pattern has been observed in tasks assessing spatial and verbal working memory, semantic memory, and non-autobiographical episodic memory. Such impairments may be less pronounced among experienced psychedelic users. Classic psychedelics also increase the vividness of autobiographical memories and frequently stimulate the recall and/or re-experiencing of autobiographical memories, often memories that are affectively intense (positively or negatively valenced) and that had been avoided and/or forgotten prior to the experience. CONCLUSIONS Classic psychedelics dose-dependently impair memory task performance but may enhance autobiographical memory. These findings are relevant to the understanding of psychological mechanisms of action of psychedelic-assisted psychotherapy.
Collapse
Affiliation(s)
- C J Healy
- Department of Psychology, The New School for Social Research, 80 5th Ave, 6th Floor, New York, NY, USA.
| |
Collapse
|
37
|
Kočárová R, Horáček J, Carhart-Harris R. Does Psychedelic Therapy Have a Transdiagnostic Action and Prophylactic Potential? Front Psychiatry 2021; 12:661233. [PMID: 34349678 PMCID: PMC8327748 DOI: 10.3389/fpsyt.2021.661233] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 06/04/2021] [Indexed: 12/20/2022] Open
Abstract
Addressing global mental health is a major 21st-century challenge. Current treatments have recognized limitations; in this context, new ones that are prophylactic and effective across diagnostic boundaries would represent a major advance. The view that there exists a core of transdiagnostic overlap between psychiatric disorders has re-emerged in recent years, and evidence that psychedelic therapy holds promise for a range of psychiatric disorders supports the position that it may be transdiagnostically effective. Here, we propose that psychedelic therapy's core, transdiagnostically relevant action lies in its ability to increase neuronal and mental plasticity, thus enhancing the potential for change, which we consider to be a key to its therapeutic benefits. Moreover, we suggest that enhanced plasticity via psychedelics, combined with a psychotherapeutic approach, can aid healthy adaptability and resilience, which are protective factors for long-term well-being. We present candidate neurological and psychological markers of this plasticity and link them with a predictive processing model of the action of psychedelics. We propose that a model of psychedelic-induced plasticity combined with an adequate therapeutic context has prophylactic and transdiagnostic potential, implying that it could have a broad, positive impact on public health.
Collapse
Affiliation(s)
- Rita Kočárová
- Department of Translational Neuroscience, National Institute of Mental Health, Klecany, Czechia.,Department of Psychology, Faculty of Arts, Charles University, Prague, Czechia.,Beyond Psychedelics, Prague, Czechia
| | - Jiří Horáček
- Department of Applied Neuroscience and Neuroimaging, National Institute of Mental Health, Klecany, Czechia.,Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Robin Carhart-Harris
- Centre for Psychedelic Research, Imperial College London, London, United Kingdom
| |
Collapse
|
38
|
Abstract
Mounting evidence suggests safety and efficacy of psychedelic compounds as potential novel therapeutics in psychiatry. Ketamine has been approved by the Food and Drug Administration in a new class of antidepressants, and 3,4-methylenedioxymethamphetamine (MDMA) is undergoing phase III clinical trials for post-traumatic stress disorder. Psilocybin and lysergic acid diethylamide (LSD) are being investigated in several phase II and phase I clinical trials. Hence, the concept of psychedelics as therapeutics may be incorporated into modern society. Here, we discuss the main known neurobiological therapeutic mechanisms of psychedelics, which are thought to be mediated by the effects of these compounds on the serotonergic (via 5-HT2A and 5-HT1A receptors) and glutamatergic [via N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors] systems. We focus on 1) neuroplasticity mediated by the modulation of mammalian target of rapamycin-, brain-derived neurotrophic factor-, and early growth response-related pathways; 2) immunomodulation via effects on the hypothalamic-pituitary-adrenal axis, nuclear factor ĸB, and cytokines such as tumor necrosis factor-α and interleukin 1, 6, and 10 production and release; and 3) modulation of serotonergic, dopaminergic, glutamatergic, GABAergic, and norepinephrinergic receptors, transporters, and turnover systems. We discuss arising concerns and ways to assess potential neurobiological changes, dependence, and immunosuppression. Although larger cohorts are required to corroborate preliminary findings, the results obtained so far are promising and represent a critical opportunity for improvement of pharmacotherapies in psychiatry, an area that has seen limited therapeutic advancement in the last 20 years. Studies are underway that are trying to decouple the psychedelic effects from the therapeutic effects of these compounds. SIGNIFICANCE STATEMENT: Psychedelic compounds are emerging as potential novel therapeutics in psychiatry. However, understanding of molecular mechanisms mediating improvement remains limited. This paper reviews the available evidence concerning the effects of psychedelic compounds on pathways that modulate neuroplasticity, immunity, and neurotransmitter systems. This work aims to be a reference for psychiatrists who may soon be faced with the possibility of prescribing psychedelic compounds as medications, helping them assess which compound(s) and regimen could be most useful for decreasing specific psychiatric symptoms.
Collapse
Affiliation(s)
- Antonio Inserra
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Danilo De Gregorio
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Gabriella Gobbi
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| |
Collapse
|
39
|
Elsilä LV, Korhonen N, Hyytiä P, Korpi ER. Acute Lysergic Acid Diethylamide Does Not Influence Reward-Driven Decision Making of C57BL/6 Mice in the Iowa Gambling Task. Front Pharmacol 2020; 11:602770. [PMID: 33343373 PMCID: PMC7745734 DOI: 10.3389/fphar.2020.602770] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 11/09/2020] [Indexed: 12/25/2022] Open
Abstract
While interest in psychedelic drugs in the fields of psychiatry and neuroscience has re-emerged in recent last decades, the general understanding of the effects of these drugs remains deficient. In particular, there are gaps in knowledge on executive functions and goal-directed behaviors both in humans and in commonly used animal models. The effects of acute doses of psychedelic lysergic acid diethylamide (LSD) on reward-driven decision making were explored using the mouse version of the Iowa Gambling Task. A total of 15 mice were trained to perform in a touch-screen adaptation of the rodent version of the Iowa Gambling Task, after which single acute doses of LSD (0.025, 0.1, 0.2, 0.4 mg/kg), serotonin 2A receptor-selective agonist 25CN-NBOH (1.5 mg/kg), d-amphetamine (2.0 mg/kg), and saline were administered before the trial. 25CN-NBOH and the three lowest doses of LSD showed no statistically significant changes in option selection or in general functioning during the gambling task trials. The highest dose of LSD (0.4 mg/kg) significantly decreased premature responding and increased the omission rate, but had no effect on option selection in comparison with the saline control. Amphetamine significantly decreased the correct responses and premature responding while increasing the omission rate. In conclusion, mice can perform previously learned, reward-driven decision-making tasks while under the acute influence of LSD at a commonly used dose range.
Collapse
Affiliation(s)
- Lauri V Elsilä
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Nuppu Korhonen
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Petri Hyytiä
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| |
Collapse
|
40
|
Aquili L. The Role of Tryptophan and Tyrosine in Executive Function and Reward Processing. Int J Tryptophan Res 2020; 13:1178646920964825. [PMID: 33149600 PMCID: PMC7586026 DOI: 10.1177/1178646920964825] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/10/2020] [Indexed: 01/31/2023] Open
Abstract
The serotonergic precursor tryptophan and the dopaminergic precursor tyrosine have been shown to be important modulators of mood, behaviour and cognition. Specifically, research on the function of tryptophan has characterised this molecule as particularly relevant in the context of pathological disorders such as depression. Moreover, a large body of evidence has now been accumulated to suggest that tryptophan may also be involved in executive function and reward processing. Despite some clear differentiation with tryptophan, the data reviewed in this paper illustrates that tyrosine shares similar functions with tryptophan in the regulation of executive function and reward, and that these processes in turn, rather than acting in isolation, causally influence each other.
Collapse
Affiliation(s)
- Luca Aquili
- College of Health & Human Sciences, Charles Darwin University, Darwin, Northern Territory, Australia
| |
Collapse
|
41
|
Abstract
Microdosing psychedelics is the repeated use of small doses of, for example, lysergic acid diethylamide (LSD) and psilocybin, typically for a few weeks. Despite the popular and scientific attention in recent years, and claims by users that it has therapeutic value in affective disorders like depression, little scientific knowledge is available to back this. The purpose of this review was to investigate whether there are scientific grounds to state that this practice could be helpful in the treatment of affective disorders, and safe to use repeatedly. To that end, the literature (PubMed, MedLine) was searched, looking for (controlled) experimental studies with low doses of LSD and/or psilocybin, in healthy volunteers and patient samples. After a selection process and the addition of relevant articles, 14 experimental studies entered this review. Findings show that both LSD (10-20 mcg) and psilocybin (<1-3 mg) have subtle (positive) effects on cognitive processes (time perception, convergent and divergent thinking) and brain regions involved in affective processes. Besides the pleasant experience, increased anxiety and a cycling pattern of depressive and euphoric mood were also found. With regard to safety, it was demonstrated that low doses are well tolerated (in healthy volunteers) and have no-to-minimal effects on physiological measures. While it is yet unclear whether psychedelic microdosing is of therapeutic value for depression, the aforementioned effects on selective processes suggest that low doses of psychedelics could play a role in depression by inducing some kind of cognitive flexibility, which might lead to decreased rumination. While previous studies were conducted mostly in small samples of healthy volunteers, future placebo-controlled clinical trials in depressed patients are required to understand the therapeutic value of microdosing psychedelics, how this differs from therapy using full psychedelic doses, and whether different psychedelics have different effect patterns. The proposed research will give new insights into the potential of future alternative psychiatric treatment forms that are fiercely needed.
Collapse
Affiliation(s)
- Kim P.C. Kuypers
- Department of Neuropsychology & Psychopharmacology, Faculty of Psychology & Neuroscience, Maastricht University, PB 616, 6200 MD, the Netherlands
| |
Collapse
|
42
|
Heuschkel K, Kuypers KP. Depression, Mindfulness, and Psilocybin: Possible Complementary Effects of Mindfulness Meditation and Psilocybin in the Treatment of Depression. A Review. Front Psychiatry 2020; 11:224. [PMID: 32296353 PMCID: PMC7136554 DOI: 10.3389/fpsyt.2020.00224] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 03/06/2020] [Indexed: 12/28/2022] Open
Abstract
Depression is a major public health problem that affects approximately 4.4% of the global population. Since conventional pharmacotherapies and psychotherapies are only partially effective, as demonstrated by the number of patients failing to achieve remission, alternative treatments are needed. Mindfulness meditation (MM) and psilocybin represent two promising novel treatments that might even have complementary therapeutic effects when combined. Since the current literature is limited to theoretical and empirical underpinnings of either treatment alone, the present review aimed to identify possible complementary effects that may be relevant to the treatment of depression. To that end, the individual effects of MM and psilocybin, and their underlying working mechanisms, were compared on a non-exhaustive selection of six prominent psychological and biological processes that are well known to show impairments in patients suffering from major depression disorder, that is mood, executive functioning, social skills, neuroplasticity, core neural networks, and neuroendocrine and neuroimmunological levels. Based on predefined search strings used in two online databases (PubMed and Google Scholar) 1129 articles were identified. After screening title and abstract for relevance related to the question, 82 articles were retained and 11 were added after reference list search, resulting in 93 articles included in the review. Findings show that MM and psilocybin exert similar effects on mood, social skills, and neuroplasticity; different effects were found on executive functioning, neural core networks, and neuroendocrine and neuroimmune system markers. Potential mechanisms of MM's effects are enhanced affective self-regulation through mental strategies, optimization of stress reactivity, and structural and functional adjustments of prefrontal and limbic areas; psilocybin's effects might be established via attenuation of cognitive associations through deep personal insights, cognitive disinhibition, and global neural network disintegration. It is suggested that, when used in combination, MM and psilocybin could exert complementary effects by potentiating or prolonging mutual positive effects, for example, MM potentially facilitating psilocybin-induced peak experiences. Future placebo-controlled double-blind randomized trials focusing on psilocybin-assisted mindfulness-based therapy will provide knowledge about whether the proposed combination of therapies maximizes their efficacy in the treatment of depression or depressive symptomatology.
Collapse
Affiliation(s)
| | - Kim P.C. Kuypers
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| |
Collapse
|