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Sinha JK, Trisal A, Ghosh S, Gupta S, Singh KK, Han SS, Mahapatra M, Abomughaid MM, Abomughayedh AM, Almutary AG, Iqbal D, Bhaskar R, Mishra PC, Jha SK, Jha NK, Singh AK. Psychedelics for alzheimer's disease-related dementia: Unveiling therapeutic possibilities and pathways. Ageing Res Rev 2024; 96:102211. [PMID: 38307424 DOI: 10.1016/j.arr.2024.102211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 02/04/2024]
Abstract
Psychedelics have traditionally been used for spiritual and recreational purposes, but recent developments in psychotherapy have highlighted their potential as therapeutic agents. These compounds, which act as potent 5-hydroxytryptamine (5HT) agonists, have been recognized for their ability to enhance neural plasticity through the activation of the serotoninergic and glutamatergic systems. However, the implications of these findings for the treatment of neurodegenerative disorders, particularly dementia, have not been fully explored. In recent years, studies have revealed the modulatory and beneficial effects of psychedelics in the context of dementia, specifically Alzheimer's disease (AD)-related dementia, which lacks a definitive cure. Psychedelics such as N,N-dimethyltryptamine (DMT), lysergic acid diethylamide (LSD), and Psilocybin have shown potential in mitigating the effects of this debilitating disease. These compounds not only target neurotransmitter imbalances but also act at the molecular level to modulate signalling pathways in AD, including the brain-derived neurotrophic factor signalling pathway and the subsequent activation of mammalian target of rapamycin and other autophagy regulators. Therefore, the controlled and dose-dependent administration of psychedelics represents a novel therapeutic intervention worth exploring and considering for the development of drugs for the treatment of AD-related dementia. In this article, we critically examined the literature that sheds light on the therapeutic possibilities and pathways of psychedelics for AD-related dementia. While this emerging field of research holds great promise, further studies are necessary to elucidate the long-term safety, efficacy, and optimal treatment protocols. Ultimately, the integration of psychedelics into the current treatment paradigm may provide a transformative approach for addressing the unmet needs of individuals living with AD-related dementia and their caregivers.
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Affiliation(s)
| | - Anchal Trisal
- Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Shampa Ghosh
- GloNeuro, Sector 107, Vishwakarma Road, Noida 201301, India
| | - Saurabh Gupta
- Department of Biotechnology, GLA University, Mathura, Uttar Pradesh, India
| | - Krishna Kumar Singh
- Symbiosis Centre for Information Technology (SCIT), Rajiv Gandhi InfoTech Park, Hinjawadi, Pune, Maharashtra 411057, India
| | - Sung Soo Han
- School of Chemical Engineering, Yeungnam University, Gyeonsang 38541, the Republic of Korea; Research Institute of Cell Culture, Yeungnam University, 280 Daehak-Ro, Gyeongsan 38541, the Republic of Korea
| | | | - Mosleh Mohammad Abomughaid
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, University of Bisha, Bisha 61922, Saudi Arabia
| | - Ali M Abomughayedh
- Pharmacy Department, Aseer Central Hospital, Ministry of Health, Saudi Arabia
| | - Abdulmajeed G Almutary
- Department of Biomedical Sciences, College of Health Sciences, Abu Dhabi University, Abu Dhabi P.O. Box 59911, United Arab Emirates
| | - Danish Iqbal
- Department of Health Information Management, College of Applied Medical Sciences, Buraydah Private Colleges, Buraydah 51418, Saudi Arabia
| | - Rakesh Bhaskar
- School of Chemical Engineering, Yeungnam University, Gyeonsang 38541, the Republic of Korea; Research Institute of Cell Culture, Yeungnam University, 280 Daehak-Ro, Gyeongsan 38541, the Republic of Korea.
| | - Prabhu Chandra Mishra
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, India
| | - Saurabh Kumar Jha
- Department of Zoology, Kalindi College, University of Delhi, 110008, India.
| | - Niraj Kumar Jha
- Centre for Global Health Research, Saveetha Medical College, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India; Centre of Research Impact and Outcome, Chitkara University, Rajpura 140401, Punjab, India; School of Bioengineering & Biosciences, Lovely Professional University, Phagwara 144411, India; Department of Biotechnology Engineering and Food Technology, Chandigarh University, Mohali, India.
| | - Abhishek Kumar Singh
- Manipal Centre for Biotherapeutics Research, Manipal Academy of Higher Education, Manipal, Karnataka 576104, India.
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Videira NB, Nair V, Paquet V, Calhoun D. The changing outlook of psychedelic drugs: The importance of risk assessment and occupational exposure limits. J Appl Toxicol 2024; 44:216-234. [PMID: 37646119 DOI: 10.1002/jat.4533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/25/2023] [Accepted: 08/11/2023] [Indexed: 09/01/2023]
Abstract
Serotonergic psychedelics, such as lysergic acid diethylamide (LSD), psilocybin, dimethyltryptamine (DMT), and 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), are currently being investigated for the treatment of psychiatric disorders such as depression and anxiety. Clinical trials with psilocybin and LSD have shown improvement in emotional and psychological scores. Although these drugs are reported to be safe in a controlled environment (such as clinical trials), exposure to low doses of these drugs can result in psychedelic effects, and therefore, occupational safety is an important consideration to prevent adverse effects in the workplace from low daily exposure. This article will discuss the factors involved in the derivation of occupational exposure limits (OELs) and risk assessment of these psychedelic drugs. To support the OEL derivations of psychedelic drugs, information regarding their mechanism of action, adverse effect profiles, pharmacokinetics, clinical effects, and nonclinical toxicity were considered. Additionally, psilocybin and LSD, which are the most extensively researched psychedelic substances, are employed as illustrative examples in case studies. The OELs derived for psilocybin and for LSD are 0.05 and 0.002 μg/m3 , respectively, which indicates that these are highly hazardous compounds, and it is important to take into account suitable safety measures and risk-management strategies in order to minimize workplace exposure.
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Affiliation(s)
| | | | - Valérie Paquet
- formerly Affygility Solutions, Broomfield, Colorado, USA
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Kolasa M, Faron-Górecka A. Preclinical models of treatment-resistant depression: challenges and perspectives. Pharmacol Rep 2023; 75:1326-1340. [PMID: 37882914 PMCID: PMC10661811 DOI: 10.1007/s43440-023-00542-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/06/2023] [Accepted: 10/06/2023] [Indexed: 10/27/2023]
Abstract
Treatment-resistant depression (TRD) is a subgroup of major depressive disorder in which the use of classical antidepressant treatments fails to achieve satisfactory treatment results. Although there are various definitions and grading models for TRD, common criteria for assessing TRD have still not been established. However, a common feature of any TRD model is the lack of response to at least two attempts at antidepressant pharmacotherapy. The causes of TRD are not known; nevertheless, it is estimated that even 60% of TRD patients are so-called pseudo-TRD patients, in which multiple biological factors, e.g., gender, age, and hormonal disturbances are concomitant with depression and involved in antidepressant drug resistance. Whereas the phenomenon of TRD is a complex disorder difficult to diagnose and successfully treat, the search for new treatment strategies is a significant challenge of modern pharmacology. It seems that despite the complexity of the TRD phenomenon, some useful animal models of TRD meet the construct, the face, and the predictive validity criteria. Based on the literature and our own experiences, we will discuss the utility of animals exposed to the stress paradigm (chronic mild stress, CMS), and the Wistar Kyoto rat strain representing an endogenous model of TRD. In this review, we will focus on reviewing research on existing and novel therapies for TRD, including ketamine, deep brain stimulation (DBS), and psychedelic drugs in the context of preclinical studies in representative animal models of TRD.
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Affiliation(s)
- Magdalena Kolasa
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Agata Faron-Górecka
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland.
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Gattuso JJ, Wilson C, Hannan AJ, Renoir T. Psilocybin as a lead candidate molecule in preclinical therapeutic studies of psychiatric disorders: A systematic review. J Neurochem 2023. [PMID: 38019032 DOI: 10.1111/jnc.16017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 11/02/2023] [Accepted: 11/10/2023] [Indexed: 11/30/2023]
Abstract
Psilocybin is the main psychoactive compound found in hallucinogenic/magic mushrooms and can bind to both serotonergic and tropomyosin receptor kinase b (TrkB) receptors. Psilocybin has begun to show efficacy for a range of neuropsychiatric conditions, including treatment-resistant depression and anxiety disorders; however, neurobiological mechanisms are still being elucidated. Clinical research has found that psilocybin can alter functional connectivity patterns in human brains, which is often associated with therapeutic outcomes. However, preclinical research affords the opportunity to assess the potential cellular mechanisms by which psilocybin may exert its therapeutic effects. Preclinical rodent models can also facilitate a more tightly controlled experimental context and minimise placebo effects. Furthermore, where there is a rationale, preclinical researchers can investigate psilocybin administration in neuropsychiatric conditions that have not yet been researched clinically. As a result, we have systematically reviewed the knowledge base, identifying 82 preclinical studies which were screened based on specific criteria. This resulted in the exclusion of 44 articles, with 34 articles being included in the main review and another 2 articles included as Supporting Information materials. We found that psilocybin shows promise as a lead candidate molecule for treating a variety of neuropsychiatric conditions, albeit showing the most efficacy for depression. We discuss the experimental findings, and identify possible mechanisms whereby psilocybin could invoke therapeutic changes. Furthermore, we critically evaluate the between-study heterogeneity and possible future research avenues. Our review suggests that preclinical rodent models can provide valid and translatable tools for researching novel psilocybin-induced molecular and cellular mechanisms, and therapeutic outcomes.
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Affiliation(s)
- James J Gattuso
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Carey Wilson
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Thibault Renoir
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia
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Malikowska-Racia N, Koniewski M, Golebiowska J, Popik P. Acute but not long-lasting antidepressant-like effect of psilocybin in differential reinforcement of low-rate 72 schedule in rats. J Psychopharmacol 2023; 37:1149-1156. [PMID: 37842884 DOI: 10.1177/02698811231205692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
BACKGROUND In clinical studies, psychedelics including psilocybin and D-lysergic acid diethylamide (LSD) demonstrate rapid and persistent antidepressant effects. Since the effective treatment with psychedelics is usually provided with psychotherapy, it is debatable whether their prolonged efficacy can be observed in infrahuman species. Preclinical reports on psychedelics' effects most often address their acute actions, and different tests and models provide inconsistent results. The goal of this study was to examine whether the treatment with psilocybin and/or LSD would demonstrate immediate and/or sustained antidepressant-like effects in the differential reinforcement of low-rate responding (DRL) schedule in rats. In contrast to the antidepressant screening tools, the DRL 72s test is known to detect antidepressants with high predictive validity as it differentiates clinically effective antidepressants from other psychoactive drugs in non-stressed animals. METHODS Adult male Sprague Dawley rats were injected over three consecutive days with psilocybin (1 mg/kg), LSD (0.08 mg/kg), or saline and then tested in DRL 72s for the following 4 weeks. RESULTS Treatment with psilocybin but not LSD demonstrated an immediate antidepressant-like effect, manifested as an increased number of reinforced presses and response efficiency. By contrast, neither of the drugs showed a long-term (up to 4 weeks following administration) antidepressant-like effect. CONCLUSIONS Using DRL 72s schedule of reinforcement, we demonstrated the acute antidepressant-like effect of psilocybin but not of LSD, and failed to detect their persistent antidepressant-like efficacy. The present study suggests that the detection of long-lasting antidepressant-like activity in rats could be challenging and may require entirely novel behavioral methods.
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Affiliation(s)
- Natalia Malikowska-Racia
- Department of Behavioral Neuroscience and Drug Development, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Maciej Koniewski
- Department of Philosophy, Institute of Sociology, Jagiellonian University, Kraków, Poland
| | - Joanna Golebiowska
- Department of Behavioral Neuroscience and Drug Development, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Piotr Popik
- Department of Behavioral Neuroscience and Drug Development, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
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Sałaciak K, Koszałka A, Lustyk K, Żmudzka E, Jagielska A, Pytka K. Memory impairments in rodent depression models: A link with depression theories. Prog Neuropsychopharmacol Biol Psychiatry 2023; 125:110774. [PMID: 37088171 DOI: 10.1016/j.pnpbp.2023.110774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 04/11/2023] [Accepted: 04/20/2023] [Indexed: 04/25/2023]
Abstract
More than 80% of depressed patients struggle with learning new tasks, remembering positive events, or concentrating on a single topic. These neurocognitive deficits accompanying depression may be linked to functional and structural changes in the prefrontal cortex and hippocampus. However, their mechanisms are not yet completely understood. We conducted a narrative review of articles regarding animal studies to assess the state of knowledge. First, we argue the contribution of changes in neurotransmitters and hormone levels in the pathomechanism of cognitive dysfunction in animal depression models. Then, we used numerous neuroinflammation studies to explore its possible implication in cognitive decline. Encouragingly, we also observed a positive correlation between increased oxidative stress and a depressive-like state with concomitant memory deficits. Finally, we discuss the undeniable role of neurotrophin deficits in developing cognitive decline in animal models of depression. This review reveals the complexity of depression-related memory impairments and highlights the potential clinical importance of gathered findings for developing more reliable animal models and designing novel antidepressants with procognitive properties.
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Affiliation(s)
- Kinga Sałaciak
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Krakow 30-688, Poland
| | - Aleksandra Koszałka
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Krakow 30-688, Poland
| | - Klaudia Lustyk
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Krakow 30-688, Poland
| | - Elżbieta Żmudzka
- Department of Social Pharmacy, Faculty of Pharmacy, Jagiellonian University Medical College Medyczna, 9 Street, Kraków 30-688, Poland
| | - Angelika Jagielska
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Krakow 30-688, Poland
| | - Karolina Pytka
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Krakow 30-688, Poland.
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Lewis V, Bonniwell EM, Lanham JK, Ghaffari A, Sheshbaradaran H, Cao AB, Calkins MM, Bautista-Carro MA, Arsenault E, Telfer A, Taghavi-Abkuh FF, Malcolm NJ, El Sayegh F, Abizaid A, Schmid Y, Morton K, Halberstadt AL, Aguilar-Valles A, McCorvy JD. A non-hallucinogenic LSD analog with therapeutic potential for mood disorders. Cell Rep 2023; 42:112203. [PMID: 36884348 PMCID: PMC10112881 DOI: 10.1016/j.celrep.2023.112203] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/30/2022] [Accepted: 02/16/2023] [Indexed: 03/08/2023] Open
Abstract
Hallucinations limit widespread therapeutic use of psychedelics as rapidly acting antidepressants. Here we profiled the non-hallucinogenic lysergic acid diethylamide (LSD) analog 2-bromo-LSD (2-Br-LSD) at more than 33 aminergic G protein-coupled receptors (GPCRs). 2-Br-LSD shows partial agonism at several aminergic GPCRs, including 5-HT2A, and does not induce the head-twitch response (HTR) in mice, supporting its classification as a non-hallucinogenic 5-HT2A partial agonist. Unlike LSD, 2-Br-LSD lacks 5-HT2B agonism, an effect linked to cardiac valvulopathy. Additionally, 2-Br-LSD produces weak 5-HT2A β-arrestin recruitment and internalization in vitro and does not induce tolerance in vivo after repeated administration. 2-Br-LSD induces dendritogenesis and spinogenesis in cultured rat cortical neurons and increases active coping behavior in mice, an effect blocked by the 5-HT2A-selective antagonist volinanserin (M100907). 2-Br-LSD also reverses the behavioral effects of chronic stress. Overall, 2-Br-LSD has an improved pharmacological profile compared with LSD and may have profound therapeutic value for mood disorders and other indications.
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Affiliation(s)
- Vern Lewis
- Department of Neuroscience, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Emma M Bonniwell
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Janelle K Lanham
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Abdi Ghaffari
- BetterLife Pharma Inc., Vancouver, BC V6H 1A6, Canada
| | | | - Andrew B Cao
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Maggie M Calkins
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | | | - Emily Arsenault
- Department of Neuroscience, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Andre Telfer
- Department of Neuroscience, Carleton University, Ottawa, ON K1S 5B6, Canada
| | | | - Nicholas J Malcolm
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Fatema El Sayegh
- Department of Neuroscience, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Alfonso Abizaid
- Department of Neuroscience, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Yasmin Schmid
- Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kathleen Morton
- Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Adam L Halberstadt
- Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA.
| | | | - John D McCorvy
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Carhart-Harris RL, Chandaria S, Erritzoe DE, Gazzaley A, Girn M, Kettner H, Mediano PAM, Nutt DJ, Rosas FE, Roseman L, Timmermann C, Weiss B, Zeifman RJ, Friston KJ. Canalization and plasticity in psychopathology. Neuropharmacology 2023; 226:109398. [PMID: 36584883 DOI: 10.1016/j.neuropharm.2022.109398] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/01/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022]
Abstract
This theoretical article revives a classical bridging construct, canalization, to describe a new model of a general factor of psychopathology. To achieve this, we have distinguished between two types of plasticity, an early one that we call 'TEMP' for 'Temperature or Entropy Mediated Plasticity', and another, we call 'canalization', which is close to Hebbian plasticity. These two forms of plasticity can be most easily distinguished by their relationship to 'precision' or inverse variance; TEMP relates to increased model variance or decreased precision, whereas the opposite is true for canalization. TEMP also subsumes increased learning rate, (Ising) temperature and entropy. Dictionary definitions of 'plasticity' describe it as the property of being easily shaped or molded; TEMP is the better match for this. Importantly, we propose that 'pathological' phenotypes develop via mechanisms of canalization or increased model precision, as a defensive response to adversity and associated distress or dysphoria. Our model states that canalization entrenches in psychopathology, narrowing the phenotypic state-space as the agent develops expertise in their pathology. We suggest that TEMP - combined with gently guiding psychological support - can counter canalization. We address questions of whether and when canalization is adaptive versus maladaptive, furnish our model with references to basic and human neuroscience, and offer concrete experiments and measures to test its main hypotheses and implications. This article is part of the Special Issue on "National Institutes of Health Psilocybin Research Speaker Series".
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Affiliation(s)
- R L Carhart-Harris
- Psychedelics Division - Neuroscape, Department of Neurology, University of California, San Francisco, USA; Centre for Psychedelic Research, Imperial College London, UK.
| | - S Chandaria
- Centre for Psychedelic Research, Imperial College London, UK; Centre for Eudaimonia and Human Flourishing, Linacre College, University of Oxford, UK; Institute of Philosophy, School of Advanced Study, University of London, UK
| | - D E Erritzoe
- Centre for Psychedelic Research, Imperial College London, UK; CNWL-Imperial Psychopharmacology and Psychedelic Research Clinic (CIPPRS), UK
| | - A Gazzaley
- Psychedelics Division - Neuroscape, Department of Neurology, University of California, San Francisco, USA
| | - M Girn
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - H Kettner
- Psychedelics Division - Neuroscape, Department of Neurology, University of California, San Francisco, USA; Centre for Psychedelic Research, Imperial College London, UK
| | - P A M Mediano
- Department of Computing, Imperial College London, London, UK; Department of Psychology, University of Cambridge, UK
| | - D J Nutt
- Centre for Psychedelic Research, Imperial College London, UK
| | - F E Rosas
- Centre for Psychedelic Research, Imperial College London, UK; Centre for Eudaimonia and Human Flourishing, Linacre College, University of Oxford, UK; Department of Informatics, University of Sussex, UK; Centre for Complexity Science, Imperial College London, UK
| | - L Roseman
- Centre for Psychedelic Research, Imperial College London, UK; CNWL-Imperial Psychopharmacology and Psychedelic Research Clinic (CIPPRS), UK
| | - C Timmermann
- Centre for Psychedelic Research, Imperial College London, UK; CNWL-Imperial Psychopharmacology and Psychedelic Research Clinic (CIPPRS), UK
| | - B Weiss
- Centre for Psychedelic Research, Imperial College London, UK; CNWL-Imperial Psychopharmacology and Psychedelic Research Clinic (CIPPRS), UK
| | - R J Zeifman
- Centre for Psychedelic Research, Imperial College London, UK; NYU Langone Center for Psychedelic Medicine, NYU Grossman School of Medicine, USA
| | - K J Friston
- Wellcome Centre for Human Neuroimaging, University College London, UK
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Ponomarenko P, Seragnoli F, Calder A, Oehen P, Hasler G. Can psychedelics enhance group psychotherapy? A discussion on the therapeutic factors. J Psychopharmacol 2023:2698811231155117. [PMID: 36855289 DOI: 10.1177/02698811231155117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
BACKGROUND Despite the growth of psychedelic research, psychedelic-assisted group psychotherapy (PAGP) has received little attention in comparison to individual psychedelic-assisted psychotherapy models. METHODS In this article, we aim to discuss the therapeutic potential of PAGP, as well as outline existing models and the challenges of this approach. Using Irvin Yalom's 11 therapeutic factors of group therapy as a basic framework, we analyse current literature from clinical studies and neurobiological research relative to the topic of PAGP. RESULTS We argue that combining psychedelic substances and group psychotherapy may prove beneficial for increasing group connectedness and interpersonal learning, potentially enhancing prosocial behaviour with direct opportunities to practice newly acquired knowledge about previously maladaptive behavioural patterns. Challenges regarding this approach include a more rigid therapy structure and potential loss of openness from patients, which may be ameliorated by adequate therapeutic training. CONCLUSION We hope for this article to support clinical research on PAGP by presenting a therapeutic framework and outlining its mechanisms and challenges.
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Affiliation(s)
| | | | - Abigail Calder
- Department of Medicine, University of Freiburg, Villars-sur-Glâne, Switzerland
| | - Peter Oehen
- Private Practice for Psychiatry and Psychotherapy, Biberist, Switzerland
| | - Gregor Hasler
- Department of Medicine, University of Freiburg, Villars-sur-Glâne, Switzerland
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Buzzelli V, Carbone E, Manduca A, Schiavi S, Feo A, Perederiy JV, Ambert KH, Hausman M, Trezza V. Psilocybin mitigates the cognitive deficits observed in a rat model of Fragile X syndrome. Psychopharmacology (Berl) 2023; 240:137-147. [PMID: 36469097 DOI: 10.1007/s00213-022-06286-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 11/20/2022] [Indexed: 12/12/2022]
Abstract
RATIONALE Fragile X syndrome (FXS) is the most common form of inherited intellectual disability (ID) and the leading monogenic cause of autism spectrum disorder (ASD). Serotonergic neurotransmission has a key role in the modulation of neuronal activity during development, and therefore, it has been hypothesized to be involved in ASD and co-occurring conditions including FXS. As serotonin is involved in synaptic remodeling and maturation, serotonergic insufficiency during childhood may have a compounding effect on brain patterning in neurodevelopmental disorders, manifesting as behavioral and emotional symptoms. Thus, compounds that stimulate serotonergic signaling such as psilocybin may offer promise as effective early interventions for developmental disorders such as ASD and FXS. OBJECTIVES The aim of the present study was to test whether different protocols of psilocybin administration mitigate cognitive deficits displayed by the recently validated Fmr1-Δexon 8 rat model of ASD, which is also a model of FXS. RESULTS Our results revealed that systemic and oral administration of psilocybin microdoses normalizes the aberrant cognitive performance displayed by adolescent Fmr1-Δexon 8 rats in the short-term version of the novel object recognition test-a measure of exploratory behavior, perception, and recognition. CONCLUSIONS These data support the hypothesis that serotonin-modulating drugs such as psilocybin may be useful to ameliorate ASD-related cognitive deficits. Overall, this study provides evidence of the beneficial effects of different schedules of psilocybin treatment in mitigating the short-term cognitive deficit observed in a rat model of FXS.
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Affiliation(s)
- Valeria Buzzelli
- Department of Science, Section of Biomedical Sciences and Technologies, University "Roma Tre", Viale G. Marconi 446, 00146, Rome, Italy
| | - Emilia Carbone
- Department of Science, Section of Biomedical Sciences and Technologies, University "Roma Tre", Viale G. Marconi 446, 00146, Rome, Italy
| | - Antonia Manduca
- Department of Science, Section of Biomedical Sciences and Technologies, University "Roma Tre", Viale G. Marconi 446, 00146, Rome, Italy.,Neuroendocrinology, Metabolism and Neuropharmacology Unit, IRCSS Fondazione Santa Lucia, Rome, Italy
| | - Sara Schiavi
- Department of Science, Section of Biomedical Sciences and Technologies, University "Roma Tre", Viale G. Marconi 446, 00146, Rome, Italy
| | - Alessandro Feo
- Department of Science, Section of Biomedical Sciences and Technologies, University "Roma Tre", Viale G. Marconi 446, 00146, Rome, Italy
| | | | - Kyle H Ambert
- Nova Mentis Life Science Corp., Vancouver, BC, Canada
| | | | - Viviana Trezza
- Department of Science, Section of Biomedical Sciences and Technologies, University "Roma Tre", Viale G. Marconi 446, 00146, Rome, Italy.
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11
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Calder AE, Hasler G. Towards an understanding of psychedelic-induced neuroplasticity. Neuropsychopharmacology 2023; 48:104-112. [PMID: 36123427 PMCID: PMC9700802 DOI: 10.1038/s41386-022-01389-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 12/20/2022]
Abstract
Classic psychedelics, such as LSD, psilocybin, and the DMT-containing beverage ayahuasca, show some potential to treat depression, anxiety, and addiction. Importantly, clinical improvements can last for months or years after treatment. It has been theorized that these long-term improvements arise because psychedelics rapidly and lastingly stimulate neuroplasticity. The focus of this review is on answering specific questions about the effects of psychedelics on neuroplasticity. Firstly, we review the evidence that psychedelics promote neuroplasticity and examine the cellular and molecular mechanisms behind the effects of different psychedelics on different aspects of neuroplasticity, including dendritogenesis, synaptogenesis, neurogenesis, and expression of plasticity-related genes (e.g., brain-derived neurotrophic factor and immediate early genes). We then examine where in the brain psychedelics promote neuroplasticity, particularly discussing the prefrontal cortex and hippocampus. We also examine what doses are required to produce this effect (e.g., hallucinogenic doses vs. "microdoses"), and how long purported changes in neuroplasticity last. Finally, we discuss the likely consequences of psychedelics' effects on neuroplasticity for both patients and healthy people, and we identify important research questions that would further scientific understanding of psychedelics' effects on neuroplasticity and its potential clinical applications.
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Affiliation(s)
- Abigail E. Calder
- grid.8534.a0000 0004 0478 1713University Center for Psychiatric Research, University of Fribourg, Fribourg, Switzerland
| | - Gregor Hasler
- University Center for Psychiatric Research, University of Fribourg, Fribourg, Switzerland.
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12
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Could psychedelic drugs have a role in the treatment of schizophrenia? Rationale and strategy for safe implementation. Mol Psychiatry 2023; 28:44-58. [PMID: 36280752 DOI: 10.1038/s41380-022-01832-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 10/02/2022] [Accepted: 10/07/2022] [Indexed: 01/07/2023]
Abstract
Schizophrenia is a widespread psychiatric disorder that affects 0.5-1.0% of the world's population and induces significant, long-term disability that exacts high personal and societal cost. Negative symptoms, which respond poorly to available antipsychotic drugs, are the primary cause of this disability. Association of negative symptoms with cortical atrophy and cell loss is widely reported. Psychedelic drugs are undergoing a significant renaissance in psychiatric disorders with efficacy reported in several conditions including depression, in individuals facing terminal cancer, posttraumatic stress disorder, and addiction. There is considerable evidence from preclinical studies and some support from human studies that psychedelics enhance neuroplasticity. In this Perspective, we consider the possibility that psychedelic drugs could have a role in treating cortical atrophy and cell loss in schizophrenia, and ameliorating the negative symptoms associated with these pathological manifestations. The foremost concern in treating schizophrenia patients with psychedelic drugs is induction or exacerbation of psychosis. We consider several strategies that could be implemented to mitigate the danger of psychotogenic effects and allow treatment of schizophrenia patients with psychedelics to be implemented. These include use of non-hallucinogenic derivatives, which are currently the focus of intense study, implementation of sub-psychedelic or microdosing, harnessing of entourage effects in extracts of psychedelic mushrooms, and blocking 5-HT2A receptor-mediated hallucinogenic effects. Preclinical studies that employ appropriate animal models are a prerequisite and clinical studies will need to be carefully designed on the basis of preclinical and translational data. Careful research in this area could significantly impact the treatment of one of the most severe and socially debilitating psychiatric disorders and open an exciting new frontier in psychopharmacology.
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13
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Pędzich BD, Medrano M, Buckinx A, Smolders I, De Bundel D. Psychedelic-Induced Serotonin 2A Receptor Downregulation Does Not Predict Swim Stress Coping in Mice. Int J Mol Sci 2022; 23:ijms232315284. [PMID: 36499610 PMCID: PMC9736085 DOI: 10.3390/ijms232315284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/25/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
Serotoninergic psychedelics such as psilocybin have been reported to elicit a long-lasting reduction in depressive symptoms. Although the main target for serotoninergic psychedelics, serotonin type 2A receptor (5-HT2A), has been established, the possible mechanism of the antidepressant action of psychedelics remains unknown. Using the mouse forced swim test model, we examined whether the administration of the synthetic serotoninergic psychedelic 2,5-dimethoxy-4-iodoamphetamine (DOI) would modulate 5-HT2A receptor levels in the medial prefrontal cortex (mPFC) and revert stress-induced changes in behavior. Mice subjected to swim stress developed a passive stress-coping strategy when tested in the forced swim test 6 days later. This change in behavior was not associated with the hypothesized increase in 5-HT2A receptor-dependent head twitch behaviors or consistent changes in 5-HT2A receptor levels in the mPFC. When DOI was administered 1 day before the forced swim test, a low dose (0.2 mg/kg i.p.) unexpectedly increased immobility while a high dose (2 mg/kg i.p.) had no significant effect on immobility. Nevertheless, DOI evoked a dose-dependent decrease in 5-HT2A levels in the mPFC of mice previously exposed to swim stress. Our findings do not support the hypothesis that the downregulation of 5-HT2A receptors in the mPFC contributes to the antidepressant-like properties of serotoninergic psychedelics.
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14
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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] [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.
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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
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15
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De Gregorio D, Inserra A, Enns JP, Markopoulos A, Pileggi M, El Rahimy Y, Lopez-Canul M, Comai S, Gobbi G. Repeated lysergic acid diethylamide (LSD) reverses stress-induced anxiety-like behavior, cortical synaptogenesis deficits and serotonergic neurotransmission decline. Neuropsychopharmacology 2022; 47:1188-1198. [PMID: 35301424 PMCID: PMC9018770 DOI: 10.1038/s41386-022-01301-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 02/02/2023]
Abstract
Lysergic acid diethylamide (LSD) is a serotonergic psychedelic compound receiving increasing interest due to putative anxiolytic and antidepressant properties. However, the potential neurobiological mechanisms mediating these effects remain elusive. Employing in vivo electrophysiology, microionthophoresis, behavioral paradigms and morphology assays, we assessed the impact of acute and chronic LSD administration on anxiety-like behavior, on the cortical dendritic spines and on the activity of serotonin (5-HT) neurons originating in the dorsal raphe nucleus (DRN) in male mice exposed to chronic restraint stress. We found that while the acute intraperitoneal (i.p.) administration of LSD (5, 15 and 30 and 60 μg/kg) did not produce any anxiolytic or antidepressant effects in non-stressed mice, the dose of 30 µg/kg (daily for 7 days) prevented the stress-induced anxiety-like behavior and the stress-induced decrease of cortical spine densitiy. Interestingly, while LSD acutely decreased the firing activity of 5-HT neurons, repeated LSD increased their basal firing rate and restored the low 5-HT firing induced by stress. This effect was accompanied by a decreased inhibitory response of 5-HT neurons to microiontophoretic applications of the 5-HT1A agonist 8-OH-DPAT (8-hydroxy-N,N-dipropyl-2-aminotetralin). In conclusion, repeated LSD prevents the exacerbation of anxiety-like behavior following chronic stress exposure, but has no behavioral effects in non-stressed mice. These effects are paralleled by increased cortical spinogenesis and an enhancement of 5-HT neurotransmission which might be due to 5-HT1A receptors desensitization. Increased cortical spine density and enhancement of serotonergic neurotransmission may thus represent a candidate mechanism which mediate the therapeutic effects of serotonergic psychedelics on stress-induced anxiety.
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Affiliation(s)
- Danilo De Gregorio
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada ,grid.15496.3f0000 0001 0439 0892Present Address: Division of Neuroscience, Vita Salute San Raffaele University, 20132 Milan, Italy
| | - Antonio Inserra
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Justine P. Enns
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Athanasios Markopoulos
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Michael Pileggi
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Youssef El Rahimy
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Martha Lopez-Canul
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Stefano Comai
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada ,grid.5608.b0000 0004 1757 3470Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy ,grid.15496.3f0000 0001 0439 0892Present Address: Division of Neuroscience, Vita Salute San Raffaele University, 20132 Milan, Italy
| | - Gabriella Gobbi
- Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1, Montreal, QC, Canada.
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16
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Wit H, Molla HM, Bershad A, Bremmer M, Lee R. Repeated low doses of LSD in healthy adults: A placebo-controlled, dose-response study. Addict Biol 2022; 27:e13143. [PMID: 35106880 DOI: 10.1111/adb.13143] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/11/2021] [Accepted: 12/21/2021] [Indexed: 12/17/2022]
Abstract
The resurgence of interest in using psychedelic drugs, including lysergic acid diethylamide (LSD), in psychiatry has drawn attention to the medically unsupervised practice of 'microdosing'. Thousands of users claim that very low doses of LSD, taken at 3-4-day intervals, improve mood and cognitive function., However, few controlled studies have described the effects of the drug when taken in this way. Here, in a double-blind controlled study, we studied the effects of four repeated doses of LSD tartrate (13 or 26 μg) or placebo, administered to healthy adults at 3-4 day intervals, on mood, cognitive performance and responses to emotional tasks. Participants were randomly assigned to one of three drug conditions: placebo (N = 18), 13 μg LSD (N = 19), or 26 μg LSD (N = 19). They attended four 5-hour drug-administration sessions separated by 3-4 days, followed by a drug-free follow-up session 3-4 days after the last session. LSD (26 μg) produced modest subjective effects including increased ratings of 'feeling a drug effect' and both stimulant-like and LSD-like effects, but the drug did not improve mood or affect performance on psychomotor or most emotional tasks. No residual effects were detected on mood or task performance on the drug-free follow-up session. We conclude that within the context of a controlled setting and a limited number of administrations, repeated low doses of LSD are safe, but produce negligible changes in mood or cognition in healthy volunteers.
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Affiliation(s)
- Harriet Wit
- Department of Psychiatry and Behavioral Neuroscience University of Chicago Chicago Illinois USA
| | - Hanna M. Molla
- Department of Psychiatry and Behavioral Neuroscience University of Chicago Chicago Illinois USA
| | - Anya Bershad
- Semel Institute for Neuroscience and Human Behavior University of California at Los Angeles Los Angeles California USA
| | - Michael Bremmer
- Department of Psychiatry and Behavioral Neuroscience University of Chicago Chicago Illinois USA
| | - Royce Lee
- Department of Psychiatry and Behavioral Neuroscience University of Chicago Chicago Illinois USA
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17
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Strumila R, Nobile B, Korsakova L, Lengvenyte A, Olie E, Lopez-Castroman J, Guillaume S, Courtet P. Psilocybin, a Naturally Occurring Indoleamine Compound, Could Be Useful to Prevent Suicidal Behaviors. Pharmaceuticals (Basel) 2021; 14:ph14121213. [PMID: 34959614 PMCID: PMC8704767 DOI: 10.3390/ph14121213] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 12/24/2022] Open
Abstract
The available interventions for people who are at risk of suicide have limited efficacy. Recently, research on new mental health treatments has started to consider psychedelic compounds, particularly psilocybin, a molecule with a few thousand years of history of use in human societies. The possible effects of psilocybin on suicidal ideation and behaviors have not been specifically studied yet; however, the current knowledge on the suicidal process and the available data on es/ketamine suggest that psylocibin could be used to modulate the thoughts and behavioral patterns in individuals who are at risk of suicidal behaviors. Here, we summarize the available evidence on the possible mechanisms underlying psilocybin positive effects on suicide risk. Major pathways related to suicidal behaviors that might be modulated by psylocibin include serotonin receptors. Specifically, psylocibin directly stimulates the serotonin 2A receptor (5HT2A), targeting the inflammatory and oxidative stress pathways and leading to a rapid increase in brain plasticity and inflammation suppression and increases in cognitive flexibility, spirituality, and empathy. We also present preliminary epidemiological data and provide a rationale for studying psilocybin in individuals with suicidal ideation or who are at risk of suicidal behaviors. This review presents a framework to understand the basis for psilocybin use in individuals who are at risk of suicidal behaviors and calls for clinical studies.
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Affiliation(s)
- Robertas Strumila
- Department of Urgent and Post Urgent Psychiatry, CHU Montpellier, 34000 Montpellier, France; (A.L.); (E.O.); (S.G.); (P.C.)
- Institute of Functional Genomics, CNRS, INSERM, University of Montpellier, 34295 Montpellier, France;
- Psychiatric Clinic, Faculty of Medicine, Institute of Clinical Medicine, Vilnius University, LT-03101 Vilnius, Lithuania
- Correspondence: (R.S.); (B.N.)
| | - Bénédicte Nobile
- Department of Urgent and Post Urgent Psychiatry, CHU Montpellier, 34000 Montpellier, France; (A.L.); (E.O.); (S.G.); (P.C.)
- Institute of Functional Genomics, CNRS, INSERM, University of Montpellier, 34295 Montpellier, France;
- Correspondence: (R.S.); (B.N.)
| | - Laura Korsakova
- Laboratory of Preclinical Drug Investigation, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50161 Kaunas, Lithuania;
| | - Aiste Lengvenyte
- Department of Urgent and Post Urgent Psychiatry, CHU Montpellier, 34000 Montpellier, France; (A.L.); (E.O.); (S.G.); (P.C.)
- Institute of Functional Genomics, CNRS, INSERM, University of Montpellier, 34295 Montpellier, France;
| | - Emilie Olie
- Department of Urgent and Post Urgent Psychiatry, CHU Montpellier, 34000 Montpellier, France; (A.L.); (E.O.); (S.G.); (P.C.)
- Institute of Functional Genomics, CNRS, INSERM, University of Montpellier, 34295 Montpellier, France;
| | - Jorge Lopez-Castroman
- Institute of Functional Genomics, CNRS, INSERM, University of Montpellier, 34295 Montpellier, France;
- Department of Adult Psychiatry, Nimes University Hospital, 44307 Nimes, France
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), 28001 Madrid, Spain
| | - Sébastien Guillaume
- Department of Urgent and Post Urgent Psychiatry, CHU Montpellier, 34000 Montpellier, France; (A.L.); (E.O.); (S.G.); (P.C.)
- Institute of Functional Genomics, CNRS, INSERM, University of Montpellier, 34295 Montpellier, France;
| | - Philippe Courtet
- Department of Urgent and Post Urgent Psychiatry, CHU Montpellier, 34000 Montpellier, France; (A.L.); (E.O.); (S.G.); (P.C.)
- Institute of Functional Genomics, CNRS, INSERM, University of Montpellier, 34295 Montpellier, France;
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18
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Saeger HN, Olson DE. Psychedelic-inspired approaches for treating neurodegenerative disorders. J Neurochem 2021; 162:109-127. [PMID: 34816433 DOI: 10.1111/jnc.15544] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/19/2021] [Accepted: 11/21/2021] [Indexed: 12/21/2022]
Abstract
Psychedelics are increasingly being recognized for their potential to treat a wide range of brain disorders including depression, post-traumatic stress disorder (PTSD), and substance use disorder. Their broad therapeutic potential might result from an ability to rescue cortical atrophy common to many neuropsychiatric and neurodegenerative diseases by impacting neurotrophic factor gene expression, activating neuronal growth and survival mechanisms, and modulating the immune system. While the therapeutic potential of psychedelics has not yet been extended to neurodegenerative disorders, we provide evidence suggesting that approaches based on psychedelic science might prove useful for treating these diseases. The primary target of psychedelics, the 5-HT2A receptor, plays key roles in cortical neuron health and is dysregulated in Alzheimer's disease. Moreover, evidence suggests that psychedelics and related compounds could prove useful for treating the behavioral and psychological symptoms of dementia (BPSD). While more research is needed to probe the effects of psychedelics in models of neurodegenerative diseases, the robust effects of these compounds on structural and functional neuroplasticity and inflammation clearly warrant further investigation.
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Affiliation(s)
- Hannah N Saeger
- Pharmacology and Toxicology Graduate Group, University of California, Davis, Davis, California, USA
| | - David E Olson
- Department of Chemistry, University of California, Davis, Davis, California, USA.,Department of Biochemistry & Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, California, USA.,Center for Neuroscience, University of California, Davis, Davis, California, USA
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19
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Aleksandrova LR, Phillips AG. Neuroplasticity as a convergent mechanism of ketamine and classical psychedelics. Trends Pharmacol Sci 2021; 42:929-942. [PMID: 34565579 DOI: 10.1016/j.tips.2021.08.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 12/20/2022]
Abstract
The emerging therapeutic efficacy of ketamine and classical psychedelics for depression has inspired tremendous interest in the underlying neurobiological mechanisms. We review preclinical and clinical evidence supporting neuroplasticity as a convergent downstream mechanism of action for these novel fast-acting antidepressants. Through their primary glutamate or serotonin receptor targets, ketamine and psychedelics [psilocybin, lysergic acid diethylamide (LSD), and N,N-dimethyltryptamine (DMT)] induce synaptic, structural, and functional changes, particularly in pyramidal neurons in the prefrontal cortex. These include increased glutamate release, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) activation, brain-derived neurotrophic factor (BDNF) and mammalian target of rapamycin (mTOR)-mediated signaling, expression of synaptic proteins, and synaptogenesis. Such influences may facilitate adaptive rewiring of pathological neurocircuitry, thus providing a neuroplasticity-focused framework to explain the robust and sustained therapeutic effects of these compounds.
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Affiliation(s)
- Lily R Aleksandrova
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada.
| | - Anthony G Phillips
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada.
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20
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Magaraggia I, Kuiperes Z, Schreiber R. Improving cognitive functioning in major depressive disorder with psychedelics: A dimensional approach. Neurobiol Learn Mem 2021; 183:107467. [PMID: 34048913 DOI: 10.1016/j.nlm.2021.107467] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/06/2021] [Accepted: 05/23/2021] [Indexed: 12/28/2022]
Abstract
The high symptomatic and biological heterogeneity of major depressive disorder (MDD) makes it very difficult to find broadly efficacious treatments that work against all symptoms. Concentrating on single core symptoms that are biologically well understood might consist of a more viable approach. The Research Domain Criteria (RDoC) framework is a trans-diagnostic dimensional approach that focuses on symptoms and their underlying neurobiology. Evidence is accumulating that psychedelics may possess antidepressant activity, and this can potentially be explained through a multi-level (psychobiological, circuitry, (sub)cellular and molecular) analysis of the cognitive systems RDoC domain. Cognitive deficits, such as negative emotional processing and negativity bias, often lead to depressive rumination. Psychedelics can increase long-term cognitive flexibility, leading to normalization of negativity bias and reduction in rumination. We propose a theoretical model that explains how psychedelics can reduce the negativity bias in depressed patients. At the psychobiological level, we hypothesize that the negativity bias in MDD is due to impaired pattern separation and that psychedelics such as psilocybin help in depression because they enhance pattern separation and hence reduce negativity bias. Pattern separation is a mnemonic process that relies on adult hippocampal neurogenesis, where similar inputs are made more distinct, which is essential for optimal encoding of contextual information. Impairment in this process may underlie the negative cognitive bias in MDD by, for example, increased pattern separation of cues with a negative valence that can lead to excessive deliberation on aversive outcomes. On the (sub) cellular level, psychedelics stimulate hippocampal neurogenesis as well as synaptogenesis, spinogenesis and dendritogenesis in the prefrontal cortex. Together, these effects help restoring resilience to chronic stress and lead to modulation of the major connectivity hubs of the prefrontal cortex, hippocampus, and amygdala. Based on these observations, we propose a new translational framework to guide the development of a novel generation of therapeutics to treat the cognitive symptoms in MDD.
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Affiliation(s)
- Igor Magaraggia
- Faculty of Psychology and Neuroscience, Section Neuropsychology & Psychopharmacology, Maastricht University, Maastricht, the Netherlands
| | - Zilla Kuiperes
- Faculty of Health, Medicine and Life Sciences (FHML), the Netherlands
| | - Rudy Schreiber
- Faculty of Psychology and Neuroscience, Section Neuropsychology & Psychopharmacology, Maastricht University, Maastricht, the Netherlands.
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21
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Jancke D, Herlitze S, Kringelbach ML, Deco G. Bridging the gap between single receptor type activity and whole-brain dynamics. FEBS J 2021; 289:2067-2084. [PMID: 33797854 DOI: 10.1111/febs.15855] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/15/2021] [Accepted: 03/31/2021] [Indexed: 02/05/2023]
Abstract
What is the effect of activating a single modulatory neuronal receptor type on entire brain network dynamics? Can such effect be isolated at all? These are important questions because characterizing elementary neuronal processes that influence network activity across the given anatomical backbone is fundamental to guide theories of brain function. Here, we introduce the concept of the cortical 'receptome' taking into account the distribution and densities of expression of different modulatory receptor types across the brain's anatomical connectivity matrix. By modelling whole-brain dynamics in silico, we suggest a bidirectional coupling between modulatory neurotransmission and neuronal connectivity hardware exemplified by the impact of single serotonergic (5-HT) receptor types on cortical dynamics. As experimental support of this concept, we show how optogenetic tools enable specific activation of a single 5-HT receptor type across the cortex as well as in vivo measurement of its distinct effects on cortical processing. Altogether, we demonstrate how the structural neuronal connectivity backbone and its modulation by a single neurotransmitter system allow access to a rich repertoire of different brain states that are fundamental for flexible behaviour. We further propose that irregular receptor expression patterns-genetically predisposed or acquired during a lifetime-may predispose for neuropsychiatric disorders like addiction, depression and anxiety along with distinct changes in brain state. Our long-term vision is that such diseases could be treated through rationally targeted therapeutic interventions of high specificity to eventually recover natural transitions of brain states.
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Affiliation(s)
- Dirk Jancke
- Optical Imaging Group, Institut für Neuroinformatik, Ruhr University Bochum, Germany.,International Graduate School of Neuroscience (IGSN), Ruhr University Bochum, Germany
| | - Stefan Herlitze
- Department of General Zoology and Neurobiology, Ruhr University, Bochum, Germany
| | - Morten L Kringelbach
- Department of Psychiatry, University of Oxford, UK.,Center for Music in the Brain, Department of Clinical Medicine, Aarhus University, Denmark.,Life and Health Sciences Research Institute, School of Medicine, University of Minho, Braga, Portugal.,Centre for Eudaimonia and Human Flourishing, University of Oxford, UK
| | - Gustavo Deco
- Center for Brain and Cognition, Computational Neuroscience Group, Universitat Pompeu Fabra, Barcelona, Spain.,Institució Catalana de la Recerca i Estudis Avançats, Barcelona, Spain.,Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,School of Psychological Sciences, Monash University, Clayton, Melbourne, Australia
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22
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Dos Santos RG, Hallak JE, Baker G, Dursun S. Hallucinogenic/psychedelic 5HT2A receptor agonists as rapid antidepressant therapeutics: Evidence and mechanisms of action. J Psychopharmacol 2021; 35:453-458. [PMID: 33740877 DOI: 10.1177/0269881120986422] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Major depressive disorder (MDD) is among the most prevalent mental health disorders worldwide, and it is associated with a reduced quality of life and enormous costs to health care systems. Available drug treatments show low-to-moderate response in most patients, with almost a third of patients being non-responders (treatment-resistant). Furthermore, most currently available medications need several weeks to achieve therapeutic effects, and the long-term use of these drugs is often associated with significant unwanted side effects and resultant reductions in treatment compliance. Therefore, more effective, safer, and faster-acting antidepressants with enduring effects are needed. Together with ketamine, psychedelics (or classic or serotoninergic hallucinogens) such as lysergic acid diethylamide (LSD), psilocybin, and ayahuasca are among the few compounds with recent human evidence of fast-acting antidepressant effects. Several studies in the 1950s to 1970s reported antidepressive and anxiolytic effects of these drugs, which are being confirmed by modern trials (LSD, one trial; psilocybin, five trials; ayahuasca, two trials). The effects of these drugs appear to be produced primarily by their agonism at serotonin (5-hydroxytryptamine, 5-HT) receptors, especially the 5-HT2A receptor. Considering the overall burden of MDD and the necessity of new therapeutic options, the promising (but currently limited) evidence of safety and efficacy of psychedelics has encouraged the scientific community to explore more fully their beneficial effects in MDD.
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Affiliation(s)
- Rafael Guimarães Dos Santos
- Department of Neurosciences and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil.,National Institute for Translational Medicine (INCT-TM), CNPq, Brazil
| | - Jaime Ec Hallak
- Department of Neurosciences and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil.,National Institute for Translational Medicine (INCT-TM), CNPq, Brazil.,Department of Psychiatry (Neurochemical Research Unit) and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Glen Baker
- National Institute for Translational Medicine (INCT-TM), CNPq, Brazil.,Department of Psychiatry (Neurochemical Research Unit) and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Serdar Dursun
- National Institute for Translational Medicine (INCT-TM), CNPq, Brazil.,Department of Psychiatry (Neurochemical Research Unit) and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
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23
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De Gregorio D, Aguilar-Valles A, Preller KH, Heifets BD, Hibicke M, Mitchell J, Gobbi G. Hallucinogens in Mental Health: Preclinical and Clinical Studies on LSD, Psilocybin, MDMA, and Ketamine. J Neurosci 2021; 41:891-900. [PMID: 33257322 PMCID: PMC7880300 DOI: 10.1523/jneurosci.1659-20.2020] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/29/2020] [Accepted: 10/09/2020] [Indexed: 12/24/2022] Open
Abstract
A revamped interest in the study of hallucinogens has recently emerged, especially with regard to their potential application in the treatment of psychiatric disorders. In the last decade, a plethora of preclinical and clinical studies have confirmed the efficacy of ketamine in the treatment of depression. More recently, emerging evidence has pointed out the potential therapeutic properties of psilocybin and LSD, as well as their ability to modulate functional brain connectivity. Moreover, MDMA, a compound belonging to the family of entactogens, has been demonstrated to be useful to treat post-traumatic stress disorders. In this review, the pharmacology of hallucinogenic compounds is summarized by underscoring the differences between psychedelic and nonpsychedelic hallucinogens as well as entactogens, and their behavioral effects in both animals and humans are described. Together, these data substantiate the potentials of these compounds in treating mental diseases.
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Affiliation(s)
- Danilo De Gregorio
- Department of Psychiatry, McGill University, Montreal, Quebec H3A 1A1, Canada
| | - Argel Aguilar-Valles
- Department of Neuroscience, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | - Katrin H Preller
- Department of Psychiatry, Psychotherapy and Psychosomatics, University of Zurich, CH-8032 Zurich, Switzerland
| | - Boris Dov Heifets
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California 94305
| | - Meghan Hibicke
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Jennifer Mitchell
- Department of Neurology, University of California San Francisco, San Francisco, California 94158
| | - Gabriella Gobbi
- Department of Psychiatry, McGill University, Montreal, Quebec H3A 1A1, Canada
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24
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Andersen KAA, Carhart-Harris R, Nutt DJ, Erritzoe D. Therapeutic effects of classic serotonergic psychedelics: A systematic review of modern-era clinical studies. Acta Psychiatr Scand 2021; 143:101-118. [PMID: 33125716 DOI: 10.1111/acps.13249] [Citation(s) in RCA: 110] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/05/2020] [Accepted: 10/22/2020] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To conduct a systematic review of modern-era (post-millennium) clinical studies assessing the therapeutic effects of serotonergic psychedelics drugs for mental health conditions. Although the main focus was on efficacy and safety, study characteristics, duration of antidepressants effects across studies, and the role of the subjective drug experiences were also reviewed and presented. METHOD A systematic literature search (1 Jan 2000 to 1 May 2020) was conducted in PubMed and PsychINFO for studies of patients undergoing treatment with a serotonergic psychedelic. RESULTS Data from 16 papers, representing 10 independent psychedelic-assisted therapy trials (psilocybin = 7, ayahuasca = 2, LSD = 1), were extracted, presented in figures and tables, and narratively synthesized and discussed. Across these studies, a total of 188 patients suffering either cancer- or illness-related anxiety and depression disorders (C/I-RADD), major depressive disorder (MDD), obsessive-compulsive disorder (OCD) or substance use disorder (SUD) were included. The reviewed studies established feasibility and evidence of safety, alongside promising early data of efficacy in the treatment of depression, anxiety, OCD, and tobacco and alcohol use disorders. For a majority of patients, the therapeutic effects appeared to be long-lasting (weeks-months) after only 1 to 3 treatment session(s). All studies were conducted in line with guidelines for the safe conduct of psychedelic therapy, and no severe adverse events were reported. CONCLUSION The resurrection of clinical psychedelic research provides early evidence for treatment efficacy and safety for a range of psychiatric conditions, and constitutes an exciting new treatment avenue in a health area with major unmet needs.
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Affiliation(s)
- Kristoffer A A Andersen
- Centre for Psychedelic Research, Division of Psychiatry, Imperial College London, London, UK.,Centre for Neuropsychopharmacology, Division of Psychiatry, Imperial College London, London, UK
| | - Robin Carhart-Harris
- Centre for Psychedelic Research, Division of Psychiatry, Imperial College London, London, UK
| | - David J Nutt
- Centre for Neuropsychopharmacology, Division of Psychiatry, Imperial College London, London, UK
| | - David Erritzoe
- Centre for Psychedelic Research, Division of Psychiatry, Imperial College London, London, UK.,Centre for Neuropsychopharmacology, Division of Psychiatry, Imperial College London, London, UK
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25
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Inserra A, De Gregorio D, Gobbi G. Psychedelics in Psychiatry: Neuroplastic, Immunomodulatory, and Neurotransmitter Mechanisms. Pharmacol Rev 2020; 73:202-277. [PMID: 33328244 DOI: 10.1124/pharmrev.120.000056] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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.
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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
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26
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Vann Jones SA, O’Kelly A. Psychedelics as a Treatment for Alzheimer's Disease Dementia. Front Synaptic Neurosci 2020; 12:34. [PMID: 32973482 PMCID: PMC7472664 DOI: 10.3389/fnsyn.2020.00034] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/28/2020] [Indexed: 12/15/2022] Open
Abstract
Currently, there are no disease-modifying treatments for Alzheimer's disease (AD) or any other dementia subtype. The renaissance in psychedelic research in recent years, in particular studies involving psilocybin and lysergic acid diethylamide (LSD), coupled with anecdotal reports of cognitive benefits from micro-dosing, suggests that they may have a therapeutic role in a range of psychiatric and neurological conditions due to their potential to stimulate neurogenesis, provoke neuroplastic changes and reduce neuroinflammation. This inevitably makes them interesting candidates for therapeutics in dementia. This mini-review will look at the basic science and current clinical evidence for the role of psychedelics in treating dementia, especially early AD, with a particular focus on micro-dosing of the classical psychedelics LSD and psilocybin.
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27
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Hibicke M, Landry AN, Kramer HM, Talman ZK, Nichols CD. Psychedelics, but Not Ketamine, Produce Persistent Antidepressant-like Effects in a Rodent Experimental System for the Study of Depression. ACS Chem Neurosci 2020; 11:864-871. [PMID: 32133835 DOI: 10.1021/acschemneuro.9b00493] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Psilocybin shows efficacy to alleviate depression in human clinical trials for six or more months after only one or two treatments. Another hallucinogenic drug, esketamine, has recently been U.S. Food and Drug Administration (FDA)-approved as a rapid-acting antidepressant. The mechanistic basis for the antidepressant effects of psilocybin and ketamine appear to be conserved. The efficacy of these two medications has not, however, been directly compared either clinically or preclinically. Further, whether or not a profound subjective existential experience is necessary for psilocybin to have antidepressant effects is unknown. To address these questions, we tested psilocybin, lysergic acid diethylamide (LSD), and ketamine in a rat model for depression. As in humans, a single administration of psilocybin or LSD produced persistent antidepressant-like effects in our model. In contrast, ketamine produced only a transient antidepressant-like effect. Our results indicate that classic psychedelics may have therapeutic efficacy that is more persistent than that of ketamine, and also suggest that a subjective existential experience may not be necessary for therapeutic effects.
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Affiliation(s)
- Meghan Hibicke
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States
| | - Alexus N. Landry
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States
| | - Hannah M. Kramer
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States
| | - Zoe K. Talman
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States
| | - Charles D. Nichols
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States
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28
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Winne J, Boerner BC, Malfatti T, Brisa E, Doerl J, Nogueira I, Leão KE, Leão RN. Anxiety-like behavior induced by salicylate depends on age and can be prevented by a single dose of 5-MeO-DMT. Exp Neurol 2020; 326:113175. [PMID: 31923390 DOI: 10.1016/j.expneurol.2020.113175] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/23/2019] [Accepted: 01/06/2020] [Indexed: 11/16/2022]
Abstract
Salicylate intoxication is a cause of tinnitus and comorbidly associated with anxiety in humans. In a previous work, we showed that salicylate induces anxiety-like behavior and hippocampal type 2 theta oscillations (theta2) in mice. Here we investigate if the anxiogenic effect of salicylate is dependent on age and previous tinnitus experience. We also tested whether a single dose of DMT can prevent this effect. Using microwire electrode arrays, we recorded local field potential in young (4-5- month-old) and old (11-13-month-old) mice to study the electrophysiological effect of tinnitus in the ventral hippocampus (vHipp) and medial prefrontal cortex (mPFC) in an open field arena and elevated plus maze 1h after salicylate (300mg/kg) injection. We found that anxiety-like behavior and increase in theta2 oscillations (4-6 Hz), following salicylate pre-treatment, only occurs in young (normal hearing) mice. We also show that theta2 and slow gamma oscillations increase in the vHipp and mPFC in a complementary manner during anxiety tests in the presence of salicylate. Finally, we show that pre-treating mice with a single dose of the hallucinogenic 5-MeO-DMT prevents anxiety-like behavior and the increase in theta2 and slow gamma oscillations after salicylate injection in normal hearing young mice. This work further support the hypothesis that anxiety-like behavior after salicylate injection is triggered by tinnitus and require normal hearing. Moreover, our results show that hallucinogenic compounds can be effective in treating tinnitus-related anxiety.
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Affiliation(s)
- Jessica Winne
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil; Developmental Genetics Unit, Department of Neuroscience, Uppsala University, Husarg 3, Uppsala 75234, Sweden
| | - Barbara C Boerner
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil
| | - Thawann Malfatti
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil
| | - Elis Brisa
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil
| | - Jhulimar Doerl
- Neural Development and Environment Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal, RN, Brazil
| | - Ingrid Nogueira
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil
| | - Katarina E Leão
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil
| | - Richardson N Leão
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil; Neural Development and Environment Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal, RN, Brazil.
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29
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Halberstadt AL, Chatha M, Klein AK, Wallach J, Brandt SD. Correlation between the potency of hallucinogens in the mouse head-twitch response assay and their behavioral and subjective effects in other species. Neuropharmacology 2020; 167:107933. [PMID: 31917152 DOI: 10.1016/j.neuropharm.2019.107933] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/28/2019] [Accepted: 12/31/2019] [Indexed: 12/11/2022]
Abstract
Serotonergic hallucinogens such as lysergic acid diethylamide (LSD) induce head twitches in rodents via 5-HT2A receptor activation. The goal of the present investigation was to determine whether a correlation exists between the potency of hallucinogens in the mouse head-twitch response (HTR) paradigm and their reported potencies in other species, specifically rats and humans. Dose-response experiments were conducted with phenylalkylamine and tryptamine hallucinogens in C57BL/6J mice, enlarging the available pool of HTR potency data to 41 total compounds. For agents where human data are available (n = 36), a strong positive correlation (r = 0.9448) was found between HTR potencies in mice and reported hallucinogenic potencies in humans. HTR potencies were also found to be correlated with published drug discrimination ED50 values for substitution in rats trained with either LSD (r = 0.9484, n = 16) or 2,5-dimethoxy-4-methylamphetamine (r = 0.9564, n = 21). All three of these behavioral effects (HTR in mice, hallucinogen discriminative stimulus effects in rats, and psychedelic effects in humans) have been linked to 5-HT2A receptor activation. We present evidence that hallucinogens induce these three effects with remarkably consistent potencies. In addition to having high construct validity, the HTR assay also appears to show significant predictive validity, confirming its translational relevance for predicting subjective potency of hallucinogens in humans. These findings support the use of the HTR paradigm as a preclinical model of hallucinogen psychopharmacology and in structure-activity relationship studies of hallucinogens. Future investigations with a larger number of test agents will evaluate whether the HTR assay can be used to predict the hallucinogenic potency of 5-HT2A agonists in humans. "This article is part of the special issue entitled 'Serotonin Research: Crossing Scales and Boundaries'.
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Affiliation(s)
- Adam L Halberstadt
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA; Research Service, VA San Diego Healthcare System, San Diego, CA, USA.
| | - Muhammad Chatha
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - Adam K Klein
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - Jason Wallach
- Department of Pharmaceutical Sciences, University of the Sciences, Philadelphia, PA, USA; Substance Use Disorders Institute, University of the Sciences, Philadelphia, PA, USA
| | - Simon D Brandt
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
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30
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Bershad AK, Schepers ST, Bremmer MP, Lee R, de Wit H. Acute Subjective and Behavioral Effects of Microdoses of Lysergic Acid Diethylamide in Healthy Human Volunteers. Biol Psychiatry 2019; 86:792-800. [PMID: 31331617 PMCID: PMC6814527 DOI: 10.1016/j.biopsych.2019.05.019] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/20/2019] [Accepted: 05/21/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Numerous anecdotal reports suggest that repeated use of very low doses of lysergic acid diethylamide (LSD), known as microdosing, improves mood and cognitive function. These effects are consistent both with the known actions of LSD on serotonin receptors and with limited evidence that higher doses of LSD (100-200 μg) positively bias emotion processing. Yet, the effects of such subthreshold doses of LSD have not been tested in a controlled laboratory setting. As a first step, we examined the effects of single very low doses of LSD (0-26 μg) on mood and behavior in healthy volunteers under double-blind conditions. METHODS Healthy young adults (N = 20) attended 4 laboratory sessions during which they received 0 (placebo), 6.5, 13, or 26 μg of LSD in randomized order at 1-week intervals. During expected peak drug effect, they completed mood questionnaires and behavioral tasks assessing emotion processing and cognition. Cardiovascular measures and body temperature were also assessed. RESULTS LSD produced dose-related subjective effects across the 3 doses (6.5, 13, and 26 μg). At the highest dose, the drug also increased ratings of vigor and slightly decreased positivity ratings of images with positive emotional content. Other mood measures, cognition, and physiological measures were unaffected. CONCLUSIONS Single microdoses of LSD produced orderly dose-related subjective effects in healthy volunteers. These findings indicate that a threshold dose of 13 μg of LSD might be used safely in an investigation of repeated administrations. It remains to be determined whether the drug improves mood or cognition in individuals with symptoms of depression.
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Affiliation(s)
- Anya K Bershad
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, Illinois; Interdisciplinary Scientist Training Program, University of Chicago, Chicago, Illinois
| | - Scott T Schepers
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, Illinois
| | - Michael P Bremmer
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, Illinois
| | - Royce Lee
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, Illinois
| | - Harriet de Wit
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, Illinois.
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31
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Muttoni S, Ardissino M, John C. Classical psychedelics for the treatment of depression and anxiety: A systematic review. J Affect Disord 2019; 258:11-24. [PMID: 31382100 DOI: 10.1016/j.jad.2019.07.076] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 07/10/2019] [Accepted: 07/29/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND Depression and anxiety are prevalent psychiatric disorders that carry significant morbidity. Pharmacological and psychosocial interventions are used to manage these conditions, but their efficacy is limited. Recent interest into the use of psychedelic-assisted therapy using ayahuasca, psilocybin or lysergic acid diethylamide (LSD) may be a promising alternative for patients unresponsive to traditional treatments. This review aims to determine the efficacy and tolerability of psychedelics in the management of resistant depression. METHODS Clinical trials investigating psychedelics in patients with depression and/or anxiety were searched via MEDLINE, EMBASE and PsychINFO. Efficacy was assessed by measuring symptom improvement from baseline, and tolerability was evaluated by noting the incidence and type of adverse effects reported. Risk of bias was assessed. RESULTS Seven studies, with 130 patients, were analysed in this review. Three were conducted in patients with depression, two in patients with anxiety and two in patients with both. In a supportive setting, ayahuasca, psilocybin, and LSD consistently produced immediate and significant anti-depressant and anxiolytic effects that were endured for several months. Psychedelics were well-tolerated. The most common adverse effects were transient anxiety, short-lived headaches, nausea and mild increases in heart rate and blood pressure. LIMITATIONS At present, the number of studies on this subject is very limited; and the number of participating patients within these is also limited as the treatment under investigations is a relatively novel concept. CONCLUSIONS Though further evidence is required, psychedelics appear to be effective in significantly reducing symptoms of depression and anxiety and are well-tolerated.
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Affiliation(s)
- Silvia Muttoni
- Imperial College London, School of Medicine, London, SW7 2AZ, United Kingdom
| | - Maddalena Ardissino
- Imperial College London, School of Medicine, London, SW7 2AZ, United Kingdom; Magill Department of Anaesthesia, Intensive Care and Pain Management, Chelsea and Westminster Hospital, London, SW10 9NH, United Kingdom.
| | - Christopher John
- Imperial College London, School of Medicine, London, SW7 2AZ, United Kingdom
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32
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Kuypers KPC, Ng L, Erritzoe D, Knudsen GM, Nichols CD, Nichols DE, Pani L, Soula A, Nutt D. Microdosing psychedelics: More questions than answers? An overview and suggestions for future research. J Psychopharmacol 2019; 33:1039-1057. [PMID: 31303095 PMCID: PMC6732823 DOI: 10.1177/0269881119857204] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND In the past few years, the issue of 'microdosing' psychedelics has been openly discussed in the public arena where claims have been made about their positive effect on mood state and cognitive processes such as concentration. However, there are very few scientific studies that have specifically addressed this issue, and there is no agreed scientific consensus on what microdosing is. AIM This critique paper is designed to address questions that need to be answered by future scientific studies and to offer guidelines for these studies. APPROACH Owing to its proximity for a possible approval in clinical use and short-lasting pharmacokinetics, our focus is predominantly on psilocybin. Psilocybin is allegedly, next to lysergic acid diethylamide (LSD), one of the two most frequently used psychedelics to microdose. Where relevant and available, data for other psychedelic drugs are also mentioned. CONCLUSION It is concluded that while most anecdotal reports focus on the positive experiences with microdosing, future research should also focus on potential risks of (multiple) administrations of a psychedelic in low doses. To that end, (pre)clinical studies including biological (e.g. heart rate, receptor turnover and occupancy) as well as cognitive (e.g. memory, attention) parameters have to be conducted and will shed light on the potential negative consequences microdosing could have.
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Affiliation(s)
- Kim PC Kuypers
- Department of Neuropsychology and
Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University,
Maastricht, The Netherlands
| | - Livia Ng
- Department of Psychology, University
College London, London, UK
| | - David Erritzoe
- Department of Psychology,
Neuropsychopharmacology Unit, Imperial College London, London, UK
| | - Gitte M Knudsen
- Neurobiology Research Unit,
Rigshospitalet and University of Copenhagen, Copenhagen, Denmark
| | - Charles D Nichols
- Department of Pharmacology and
Experimental Therapeutics, Louisiana State University Health Sciences Center, New
Orleans, LA, USA
| | - David E Nichols
- Purdue University College of Pharmacy,
West Lafayette, LA, USA
| | - Luca Pani
- Department of Psychiatry and Behavioral
Sciences, Psychiatry University of Miami, Miami, FL, USA
- Department of Biomedical, Metabolic
& Neural Sciences, University of Modena, Modena, Italy
| | | | - David Nutt
- Neuropsychopharmacology, Imperial
College London, London, UK
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Abstract
OBJECTIVE Psilocybin is a serotonin receptor agonist with a therapeutic potential for treatment-resistant depression and other psychiatric illnesses. We investigated whether the administration of psilocybin had an antidepressant-like effect in a rat model of depression. METHODS Using the Flinders Sensitive Line (FSL) rat model of depression, we assessed the antidepressant-like effect of psilocin and psilocybin, measured as a reduction in immobility time in the forced swim test (FST). We measured locomotor activity in an open field test (OFT) to control for stimulant properties of the drugs. We performed a set of experiments to test different doses, treatment paradigms, and timing of the tests in relation to the drug administration. RESULTS Psilocin and psilocybin showed no effect on immobility, struggling, or swimming behaviour in the FST and no effect on locomotor activity in the OFT. FSL rats did show significantly more immobility than their control strain, the Flinders Resistant Line, as expected. CONCLUSION Psilocin and psilocybin showed no antidepressant-like effect in the FSL rats, despite a positive effect in humans. This suggests that other animal models of depression and other behavioural tests may be more appropriate for translational studies in the effects of psilocybin.
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Cameron L, Benson CJ, DeFelice BC, Fiehn O, Olson DE. Chronic, Intermittent Microdoses of the Psychedelic N, N-Dimethyltryptamine (DMT) Produce Positive Effects on Mood and Anxiety in Rodents. ACS Chem Neurosci 2019; 10:3261-3270. [PMID: 30829033 PMCID: PMC6639775 DOI: 10.1021/acschemneuro.8b00692] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/14/2019] [Indexed: 12/21/2022] Open
Abstract
Drugs capable of ameliorating symptoms of depression and anxiety while also improving cognitive function and sociability are highly desirable. Anecdotal reports have suggested that serotonergic psychedelics administered in low doses on a chronic, intermittent schedule, so-called "microdosing", might produce beneficial effects on mood, anxiety, cognition, and social interaction. Here, we test this hypothesis by subjecting male and female Sprague Dawley rats to behavioral testing following the chronic, intermittent administration of low doses of the psychedelic N,N-dimethyltryptamine (DMT). The behavioral and cellular effects of this dosing regimen were distinct from those induced following a single high dose of the drug. We found that chronic, intermittent, low doses of DMT produced an antidepressant-like phenotype and enhanced fear extinction learning without impacting working memory or social interaction. Additionally, male rats treated with DMT on this schedule gained a significant amount of body weight during the course of the study. Taken together, our results suggest that psychedelic microdosing may alleviate symptoms of mood and anxiety disorders, though the potential hazards of this practice warrant further investigation.
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Affiliation(s)
- Lindsay
P. Cameron
- Neuroscience
Graduate Program, University of California,
Davis, 1544 Newton Ct, Davis, California 95618, United States
| | - Charlie J. Benson
- Department
of Chemistry, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
| | - Brian C. DeFelice
- West
Coast Metabolomics Center, University of
California, Davis, One
Shields Avenue, Davis, California 95616, United States
| | - Oliver Fiehn
- West
Coast Metabolomics Center, University of
California, Davis, One
Shields Avenue, Davis, California 95616, United States
- Biochemistry
Department, King Abdulaziz University, Jeddah, Saudi-Arabia
| | - David E. Olson
- Department
of Chemistry, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
- Department
of Biochemistry & Molecular Medicine, School of Medicine, University of California, Davis, 2700 Stockton Blvd, Suite 2102, Sacramento, California 95817, United States
- Center for
Neuroscience, University of California,
Davis, 1544 Newton Ct, Davis, California 95618, United States
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Vrinda M, Arun S, Srikumar B, Kutty BM, Shankaranarayana Rao B. Temporal lobe epilepsy-induced neurodegeneration and cognitive deficits: Implications for aging. J Chem Neuroanat 2019; 95:146-153. [DOI: 10.1016/j.jchemneu.2018.02.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 02/16/2018] [Accepted: 02/16/2018] [Indexed: 12/12/2022]
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Rajkumar R, Dawe GS. OBscure but not OBsolete: Perturbations of the frontal cortex in common between rodent olfactory bulbectomy model and major depression. J Chem Neuroanat 2018; 91:63-100. [DOI: 10.1016/j.jchemneu.2018.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 03/02/2018] [Accepted: 04/04/2018] [Indexed: 02/08/2023]
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Barker SA. N, N-Dimethyltryptamine (DMT), an Endogenous Hallucinogen: Past, Present, and Future Research to Determine Its Role and Function. Front Neurosci 2018; 12:536. [PMID: 30127713 PMCID: PMC6088236 DOI: 10.3389/fnins.2018.00536] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 07/17/2018] [Indexed: 01/12/2023] Open
Abstract
This report provides a historical overview of research concerning the endogenous hallucinogen N, N-dimethyltryptamine (DMT), focusing on data regarding its biosynthesis and metabolism in the brain and peripheral tissues, methods and results for DMT detection in body fluids and brain, new sites of action for DMT, and new data regarding its possible physiological and therapeutic roles. Research that further elaborates its consideration as a putative neurotransmitter is also addressed. Taking these studies together, the report proposes several new directions and experiments to ascertain the role of DMT in the brain, including brain mapping of enzymes responsible for the biosynthesis of DMT, further studies to elaborate its presence and role in the pineal gland, a reconsideration of binding site data, and new administration and imaging studies. The need to resolve the "natural" role of an endogenous hallucinogen from the effects observed from peripheral administration are also emphasized.
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Affiliation(s)
- Steven A. Barker
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, United States
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Buchborn T, Lyons T, Knöpfel T. Tolerance and Tachyphylaxis to Head Twitches Induced by the 5-HT2A Agonist 25CN-NBOH in Mice. Front Pharmacol 2018; 9:17. [PMID: 29467649 PMCID: PMC5808243 DOI: 10.3389/fphar.2018.00017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 01/08/2018] [Indexed: 12/20/2022] Open
Abstract
The serotonin (5-HT) 2A receptor is the primary molecular target of serotonergic hallucinogens, which trigger large-scale perturbations of the cortex. Our understanding of how 5-HT2A activation may cause the effects of hallucinogens has been hampered by the receptor unselectivity of most of the drugs of this class. Here we used 25CN-NBOH (N-(2-hydroxybenzyl)-2,5-dimethoxy-4-cyanophenylethylamine), a newly developed selective 5-HT2A agonist, and tested it with regard to the head-twitch-response (HTR) model of 5-HT2A activity and effects on locomotion. 25CN-NBOH evoked HTRs with an inverted u-shape-like dose-response curve and highest efficacy at 1.5 mg/kg, i.p. HTR occurrence peaked within 5 min after agonist injection, and exponentially decreased to half-maximal frequency at ~11 min. Thorough habituation to the experimental procedures (including handling, saline injection, and exposure to the observational boxes 1 day before the experiment) facilitated the animals' response to 25CN-NBOH. 25CN-NBOH (1.5 mg/kg, i.p.) induced HTRs were blocked by the 5-HT2A antagonist ketanserin (0.75 mg/kg, 30 min pre), but not by the 5-HT2C antagonist SB-242084 (0.5 mg/kg, i.p., 30 min pre). SB-242084 instead slightly increased the number of HTRs occurring at a 3.0-mg/kg dose of the agonist. Apart from HTR induction, 25CN-NBOH also modestly increased locomotor activity of the mice. Repeated once-per-day injections (1.5 mg/kg, i.p.) led to reduced occurrence of 25CN-NBOH induced HTRs. This intermediate tolerance was augmented when a second (higher) dose of the drug (3.0 mg/kg) was interspersed. Short-interval tolerance (i.e., tachyphylaxis) was observed when the drug was injected twice at intervals of 1.0 and 1.5 h at either dose tested (1.5 mg/kg and 0.75 mg/kg, respectively). Inducing ketanserin-sensitive HTRs, which are dependent on environmental valences and which show signs of tachyphylaxis and tolerance, 25CN-NBOH shares striking features common to serotonergic hallucinogens. Given its distinct in vitro selectivity for 5-HT2A over non5-HT2 receptors and its behavioral dynamics, 25CN-NBOH appears to be a powerful tool for dissection of receptor-specific cortical circuit dynamics, including 5-HT2A related psychoactivity.
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Affiliation(s)
- Tobias Buchborn
- Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College London, London, United Kingdom
| | - Taylor Lyons
- Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College London, London, United Kingdom
| | - Thomas Knöpfel
- Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College London, London, United Kingdom.,Centre for Neurotechnology, Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
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Carhart-Harris RL, Bolstridge M, Day CMJ, Rucker J, Watts R, Erritzoe DE, Kaelen M, Giribaldi B, Bloomfield M, Pilling S, Rickard JA, Forbes B, Feilding A, Taylor D, Curran HV, Nutt DJ. Psilocybin with psychological support for treatment-resistant depression: six-month follow-up. Psychopharmacology (Berl) 2018; 235:399-408. [PMID: 29119217 PMCID: PMC5813086 DOI: 10.1007/s00213-017-4771-x] [Citation(s) in RCA: 433] [Impact Index Per Article: 72.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/19/2017] [Indexed: 01/30/2023]
Abstract
RATIONALE Recent clinical trials are reporting marked improvements in mental health outcomes with psychedelic drug-assisted psychotherapy. OBJECTIVES Here, we report on safety and efficacy outcomes for up to 6 months in an open-label trial of psilocybin for treatment-resistant depression. METHODS Twenty patients (six females) with (mostly) severe, unipolar, treatment-resistant major depression received two oral doses of psilocybin (10 and 25 mg, 7 days apart) in a supportive setting. Depressive symptoms were assessed from 1 week to 6 months post-treatment, with the self-rated QIDS-SR16 as the primary outcome measure. RESULTS Treatment was generally well tolerated. Relative to baseline, marked reductions in depressive symptoms were observed for the first 5 weeks post-treatment (Cohen's d = 2.2 at week 1 and 2.3 at week 5, both p < 0.001); nine and four patients met the criteria for response and remission at week 5. Results remained positive at 3 and 6 months (Cohen's d = 1.5 and 1.4, respectively, both p < 0.001). No patients sought conventional antidepressant treatment within 5 weeks of psilocybin. Reductions in depressive symptoms at 5 weeks were predicted by the quality of the acute psychedelic experience. CONCLUSIONS Although limited conclusions can be drawn about treatment efficacy from open-label trials, tolerability was good, effect sizes large and symptom improvements appeared rapidly after just two psilocybin treatment sessions and remained significant 6 months post-treatment in a treatment-resistant cohort. Psilocybin represents a promising paradigm for unresponsive depression that warrants further research in double-blind randomised control trials.
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Affiliation(s)
- R L Carhart-Harris
- Psychedelic Research Group, Centre for Neuropsychopharmacology, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK.
| | - M Bolstridge
- Psychedelic Research Group, Centre for Neuropsychopharmacology, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
- South London and Maudsley NHS Foundation Trust, London, UK
| | - C M J Day
- Psychedelic Research Group, Centre for Neuropsychopharmacology, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
- South London and Maudsley NHS Foundation Trust, London, UK
| | - J Rucker
- Psychedelic Research Group, Centre for Neuropsychopharmacology, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
- The Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- South West London and St George's Mental Health NHS Trust, London, UK
| | - R Watts
- Psychedelic Research Group, Centre for Neuropsychopharmacology, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - D E Erritzoe
- Psychedelic Research Group, Centre for Neuropsychopharmacology, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - M Kaelen
- Psychedelic Research Group, Centre for Neuropsychopharmacology, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - B Giribaldi
- Psychedelic Research Group, Centre for Neuropsychopharmacology, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - M Bloomfield
- Division of Psychiatry, University College London and Clinical Psychopharmacology Unit, University College London, London, UK
| | - S Pilling
- Clinical Psychology and Clinical Effectiveness, University College London, London, UK
| | - J A Rickard
- Barts Health Pharmaceuticals, Barts Health NHS Trust, the Royal London Hospital, London, UK
| | - B Forbes
- Institute of Pharmaceutical Science, King's College London, London, UK
| | - A Feilding
- The Beckley Foundation, Beckley Park, Oxford, UK
| | - D Taylor
- Pharmacy and Pathology, South London and Maudsley NHS Foundation Trust, London, UK
| | - H V Curran
- Clinical Psychology and Clinical Effectiveness, University College London, London, UK
- Clinical Psychopharmacology Unit, University College London, London, UK
| | - D J Nutt
- Psychedelic Research Group, Centre for Neuropsychopharmacology, Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
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Abstract
Previous attempts to identify a unified theory of brain serotonin function have largely failed to achieve consensus. In this present synthesis, we integrate previous perspectives with new and older data to create a novel bipartite model centred on the view that serotonin neurotransmission enhances two distinct adaptive responses to adversity, mediated in large part by its two most prevalent and researched brain receptors: the 5-HT1A and 5-HT2A receptors. We propose that passive coping (i.e. tolerating a source of stress) is mediated by postsynaptic 5-HT1AR signalling and characterised by stress moderation. Conversely, we argue that active coping (i.e. actively addressing a source of stress) is mediated by 5-HT2AR signalling and characterised by enhanced plasticity (defined as capacity for change). We propose that 5-HT1AR-mediated stress moderation may be the brain's default response to adversity but that an improved ability to change one's situation and/or relationship to it via 5-HT2AR-mediated plasticity may also be important - and increasingly so as the level of adversity reaches a critical point. We propose that the 5-HT1AR pathway is enhanced by conventional 5-HT reuptake blocking antidepressants such as the selective serotonin reuptake inhibitors (SSRIs), whereas the 5-HT2AR pathway is enhanced by 5-HT2AR-agonist psychedelics. This bipartite model purports to explain how different drugs (SSRIs and psychedelics) that modulate the serotonergic system in different ways, can achieve complementary adaptive and potentially therapeutic outcomes.
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Affiliation(s)
- RL Carhart-Harris
- Psychedelic Research Group, Neuropsychopharmacology Unit, Centre for Psychiatry, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK
| | - DJ Nutt
- Psychedelic Research Group, Neuropsychopharmacology Unit, Centre for Psychiatry, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK
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Dos Santos RG, Osório FL, Crippa JAS, Hallak JEC. Antidepressive and anxiolytic effects of ayahuasca: a systematic literature review of animal and human studies. BRAZILIAN JOURNAL OF PSYCHIATRY 2017; 38:65-72. [PMID: 27111702 PMCID: PMC7115465 DOI: 10.1590/1516-4446-2015-1701] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 05/05/2015] [Indexed: 01/24/2023]
Abstract
OBJECTIVE To conduct a systematic literature review of animal and human studies reporting anxiolytic or antidepressive effects of ayahuasca or some of its isolated alkaloids (dimethyltryptamine, harmine, tetrahydroharmine, and harmaline). METHODS Papers published until 3 April 2015 were retrieved from the PubMed, LILACS and SciELO databases following a comprehensive search strategy and using a predetermined set of criteria for article selection. RESULTS Five hundred and fourteen studies were identified, of which 21 met the established criteria. Studies in animals have shown anxiolytic and antidepressive effects of ayahuasca, harmine, and harmaline, and experimental studies in humans and mental health assessments of experienced ayahuasca consumers also suggest that ayahuasca is associated with reductions in anxiety and depressive symptoms. A pilot study reported rapid antidepressive effects of a single ayahuasca dose in six patients with recurrent depression. CONCLUSION Considering the need for new drugs that produce fewer adverse effects and are more effective in reducing anxiety and depression symptomatology, the described effects of ayahuasca and its alkaloids should be further investigated.
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Affiliation(s)
- Rafael G Dos Santos
- Departamento de Neurociências e Ciências do Comportamento, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Flávia L Osório
- Departamento de Neurociências e Ciências do Comportamento, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - José Alexandre S Crippa
- Departamento de Neurociências e Ciências do Comportamento, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Jaime E C Hallak
- Departamento de Neurociências e Ciências do Comportamento, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil
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Gallimore AR, Strassman RJ. A Model for the Application of Target-Controlled Intravenous Infusion for a Prolonged Immersive DMT Psychedelic Experience. Front Pharmacol 2016; 7:211. [PMID: 27471468 PMCID: PMC4944667 DOI: 10.3389/fphar.2016.00211] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 06/30/2016] [Indexed: 01/22/2023] Open
Abstract
The state of consciousness induced by N,N-dimethyltryptamine (DMT) is one of the most extraordinary of any naturally-occurring psychedelic substance. Users consistently report the complete replacement of normal subjective experience with a novel "alternate universe," often densely populated with a variety of strange objects and other highly complex visual content, including what appear to be sentient "beings." The phenomenology of the DMT state is of great interest to psychology and calls for rigorous academic enquiry. The extremely short duration of DMT effects-less than 20 min-militates against single dose administration as the ideal model for such enquiry. Using pharmacokinetic modeling and DMT blood sampling data, we demonstrate that the unique pharmacological characteristics of DMT, which also include a rapid onset and lack of acute tolerance to its subjective effects, make it amenable to administration by target-controlled intravenous infusion. This is a technology developed to maintain a stable brain concentration of anesthetic drugs during surgery. Simulations of our model demonstrate that this approach will allow research subjects to be induced into a stable and prolonged DMT experience, making it possible to carefully observe its psychological contents, and provide more extensive accounts for subsequent analyses. This model would also be valuable in performing functional neuroimaging, where subjects are required to remain under the influence of the drug for extended periods. Finally, target-controlled intravenous infusion of DMT may aid the development of unique psychotherapeutic applications of this psychedelic agent.
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Affiliation(s)
- Andrew R. Gallimore
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology Graduate UniversityOkinawa, Japan
| | - Rick J. Strassman
- Department of Psychiatry, University of New Mexico School of MedicineAlbuquerque, NM, USA
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Psilocybin with psychological support for treatment-resistant depression: an open-label feasibility study. Lancet Psychiatry 2016; 3:619-27. [PMID: 27210031 DOI: 10.1016/s2215-0366(16)30065-7] [Citation(s) in RCA: 766] [Impact Index Per Article: 95.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 03/21/2016] [Accepted: 04/14/2016] [Indexed: 11/22/2022]
Abstract
BACKGROUND Psilocybin is a serotonin receptor agonist that occurs naturally in some mushroom species. Recent studies have assessed the therapeutic potential of psilocybin for various conditions, including end-of-life anxiety, obsessive-compulsive disorder, and smoking and alcohol dependence, with promising preliminary results. Here, we aimed to investigate the feasibility, safety, and efficacy of psilocybin in patients with unipolar treatment-resistant depression. METHODS In this open-label feasibility trial, 12 patients (six men, six women) with moderate-to-severe, unipolar, treatment-resistant major depression received two oral doses of psilocybin (10 mg and 25 mg, 7 days apart) in a supportive setting. There was no control group. Psychological support was provided before, during, and after each session. The primary outcome measure for feasibility was patient-reported intensity of psilocybin's effects. Patients were monitored for adverse reactions during the dosing sessions and subsequent clinic and remote follow-up. Depressive symptoms were assessed with standard assessments from 1 week to 3 months after treatment, with the 16-item Quick Inventory of Depressive Symptoms (QIDS) serving as the primary efficacy outcome. This trial is registered with ISRCTN, number ISRCTN14426797. FINDINGS Psilocybin's acute psychedelic effects typically became detectable 30-60 min after dosing, peaked 2-3 h after dosing, and subsided to negligible levels at least 6 h after dosing. Mean self-rated intensity (on a 0-1 scale) was 0·51 (SD 0·36) for the low-dose session and 0·75 (SD 0·27) for the high-dose session. Psilocybin was well tolerated by all of the patients, and no serious or unexpected adverse events occurred. The adverse reactions we noted were transient anxiety during drug onset (all patients), transient confusion or thought disorder (nine patients), mild and transient nausea (four patients), and transient headache (four patients). Relative to baseline, depressive symptoms were markedly reduced 1 week (mean QIDS difference -11·8, 95% CI -9·15 to -14·35, p=0·002, Hedges' g=3·1) and 3 months (-9·2, 95% CI -5·69 to -12·71, p=0·003, Hedges' g=2) after high-dose treatment. Marked and sustained improvements in anxiety and anhedonia were also noted. INTERPRETATION This study provides preliminary support for the safety and efficacy of psilocybin for treatment-resistant depression and motivates further trials, with more rigorous designs, to better examine the therapeutic potential of this approach. FUNDING Medical Research Council.
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Howland RH. Antidepressant, Antipsychotic, and Hallucinogen Drugs for the Treatment of Psychiatric Disorders: A Convergence at the Serotonin-2A Receptor. J Psychosoc Nurs Ment Health Serv 2016; 54:21-4. [DOI: 10.3928/02793695-20160616-09] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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dos Santos RG, Osório FL, Crippa JAS, Riba J, Zuardi AW, Hallak JEC. Antidepressive, anxiolytic, and antiaddictive effects of ayahuasca, psilocybin and lysergic acid diethylamide (LSD): a systematic review of clinical trials published in the last 25 years. Ther Adv Psychopharmacol 2016; 6:193-213. [PMID: 27354908 PMCID: PMC4910400 DOI: 10.1177/2045125316638008] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
To date, pharmacological treatments for mood and anxiety disorders and for drug dependence show limited efficacy, leaving a large number of patients suffering severe and persistent symptoms. Preliminary studies in animals and humans suggest that ayahuasca, psilocybin and lysergic acid diethylamide (LSD) may have antidepressive, anxiolytic, and antiaddictive properties. Thus, we conducted a systematic review of clinical trials published from 1990 until 2015, assessing these therapeutic properties. Electronic searches were performed using the PubMed, LILACS, and SciELO databases. Only clinical trials published in peer-reviewed journals were included. Of these, 151 studies were identified, of which six met the established criteria. Reviewed studies suggest beneficial effects for treatment-resistant depression, anxiety and depression associated with life-threatening diseases, and tobacco and alcohol dependence. All drugs were well tolerated. In conclusion, ayahuasca, psilocybin and LSD may be useful pharmacological tools for the treatment of drug dependence, and anxiety and mood disorders, especially in treatment-resistant patients. These drugs may also be useful pharmacological tools to understand psychiatric disorders and to develop new therapeutic agents. However, all studies reviewed had small sample sizes, and half of them were open-label, proof-of-concept studies. Randomized, double-blind, placebo-controlled studies with more patients are needed to replicate these preliminary findings.
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Affiliation(s)
- Rafael G. dos Santos
- Departamento de Neurociências e Ciências do Comportamento, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Hospital das Clínicas, Terceiro Andar, Av. Bandeirantes, 3900, Ribeirão Preto, São Paulo, Brazil
| | - Flávia L. Osório
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil National Institute for Translational Medicine (INCT-TM), CNPq, Brazil
| | - José Alexandre S. Crippa
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil National Institute for Translational Medicine (INCT-TM), CNPq, Brazil
| | - Jordi Riba
- Centre d’Investigació de Medicaments, Servei de Farmacologia Clínica, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
- Human Experimental Neuropsy-chopharmacology, Institut de Recerca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
- Departament de Farmacologia i Terapèutica, Universitat Autònoma de Barcelona, Spain
- Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Barcelona, Spain
| | - Antônio W. Zuardi
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil National Institute for Translational Medicine (INCT-TM), CNPq, Brazil
| | - Jaime E. C. Hallak
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil National Institute for Translational Medicine (INCT-TM), CNPq, Brazil
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Abstract
Psychedelics (serotonergic hallucinogens) are powerful psychoactive substances that alter perception and mood and affect numerous cognitive processes. They are generally considered physiologically safe and do not lead to dependence or addiction. Their origin predates written history, and they were employed by early cultures in many sociocultural and ritual contexts. After the virtually contemporaneous discovery of (5R,8R)-(+)-lysergic acid-N,N-diethylamide (LSD)-25 and the identification of serotonin in the brain, early research focused intensively on the possibility that LSD and other psychedelics had a serotonergic basis for their action. Today there is a consensus that psychedelics are agonists or partial agonists at brain serotonin 5-hydroxytryptamine 2A receptors, with particular importance on those expressed on apical dendrites of neocortical pyramidal cells in layer V. Several useful rodent models have been developed over the years to help unravel the neurochemical correlates of serotonin 5-hydroxytryptamine 2A receptor activation in the brain, and a variety of imaging techniques have been employed to identify key brain areas that are directly affected by psychedelics. Recent and exciting developments in the field have occurred in clinical research, where several double-blind placebo-controlled phase 2 studies of psilocybin-assisted psychotherapy in patients with cancer-related psychosocial distress have demonstrated unprecedented positive relief of anxiety and depression. Two small pilot studies of psilocybin-assisted psychotherapy also have shown positive benefit in treating both alcohol and nicotine addiction. Recently, blood oxygen level-dependent functional magnetic resonance imaging and magnetoencephalography have been employed for in vivo brain imaging in humans after administration of a psychedelic, and results indicate that intravenously administered psilocybin and LSD produce decreases in oscillatory power in areas of the brain's default mode network.
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Affiliation(s)
- David E Nichols
- Eschelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina
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Zhang G, Stackman RW. The role of serotonin 5-HT2A receptors in memory and cognition. Front Pharmacol 2015; 6:225. [PMID: 26500553 PMCID: PMC4594018 DOI: 10.3389/fphar.2015.00225] [Citation(s) in RCA: 178] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/22/2015] [Indexed: 01/31/2023] Open
Abstract
Serotonin 5-HT2A receptors (5-HT2ARs) are widely distributed in the central nervous system, especially in brain region essential for learning and cognition. In addition to endogenous 5-HT, several hallucinogens, antipsychotics, and antidepressants function by targeting 5-HT2ARs. Preclinical studies show that 5-HT2AR antagonists have antipsychotic and antidepressant properties, whereas agonist ligands possess cognition-enhancing and hallucinogenic properties. Abnormal 5-HT2AR activity is associated with a number of psychiatric disorders and conditions, including depression, schizophrenia, and drug addiction. In addition to its traditional activity as a G protein-coupled receptor (GPCR), recent studies have defined novel operations of 5-HT2ARs. Here we review progress in the (1) receptor anatomy and biology: distribution, signaling, polymerization and allosteric modulation; and (2) receptor functions: learning and memory, hallucination and spatial cognition, and mental disorders. Based on the recent progress in basic research on the 5-HT2AR, it appears that post-training 5-HT2AR activation enhances non-spatial memory consolidation, while pre-training 5-HT2AR activation facilitates fear extinction. Further, the potential influence that 5-HT2AR-elicited visual hallucinations may have on visual cue (i.e., landmark) guided spatial cognition is discussed. We conclude that the development of selective 5-HT2AR modulators to target distinct signaling pathways and neural circuits represents a new possibility for treating emotional, neuropsychiatric, and neurodegenerative disorders.
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Affiliation(s)
- Gongliang Zhang
- College of Basic Medicine, Anhui Medical University Hefei, China ; Department of Biology, Charles E. Schmidt College of Science, Florida Atlantic University, Jupiter FL, USA ; Jupiter Life Science Initiative, Florida Atlantic University, Jupiter FL, USA
| | - Robert W Stackman
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter FL, USA ; Department of Psychology, Charles E. Schmidt College of Science, Florida Atlantic University, Jupiter FL, USA
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Gallimore AR. Restructuring consciousness -the psychedelic state in light of integrated information theory. Front Hum Neurosci 2015; 9:346. [PMID: 26124719 PMCID: PMC4464176 DOI: 10.3389/fnhum.2015.00346] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 05/29/2015] [Indexed: 11/13/2022] Open
Abstract
The psychological state elicited by the classic psychedelics drugs, such as LSD and psilocybin, is one of the most fascinating and yet least understood states of consciousness. However, with the advent of modern functional neuroimaging techniques, the effect of these drugs on neural activity is now being revealed, although many of the varied phenomenological features of the psychedelic state remain challenging to explain. Integrated information theory (IIT) is one of the foremost contemporary theories of consciousness, providing a mathematical formalization of both the quantity and quality of conscious experience. This theory can be applied to all known states of consciousness, including the psychedelic state. Using the results of functional neuroimaging data on the psychedelic state, the effects of psychedelic drugs on both the level and structure of consciousness can be explained in terms of the conceptual framework of IIT. This new IIT-based model of the psychedelic state provides an explanation for many of its phenomenological features, including unconstrained cognition, alterations in the structure and meaning of concepts and a sense of expanded awareness. This model also suggests that whilst cognitive flexibility, creativity, and imagination are enhanced during the psychedelic state, this occurs at the expense of cause-effect information, as well as degrading the brain's ability to organize, categorize, and differentiate the constituents of conscious experience. Furthermore, the model generates specific predictions that can be tested using a combination of functional imaging techniques, as has been applied to the study of levels of consciousness during anesthesia and following brain injury.
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Affiliation(s)
- Andrew R Gallimore
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University Okinawa, Japan
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Buchborn T, Schröder H, Dieterich DC, Grecksch G, Höllt V. Tolerance to LSD and DOB induced shaking behaviour: differential adaptations of frontocortical 5-HT(2A) and glutamate receptor binding sites. Behav Brain Res 2015; 281:62-8. [PMID: 25513973 DOI: 10.1016/j.bbr.2014.12.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Revised: 12/04/2014] [Accepted: 12/06/2014] [Indexed: 12/20/2022]
Abstract
Serotonergic hallucinogens, such as lysergic acid diethylamide (LSD) and dimethoxy-bromoamphetamine (DOB), provoke stereotype-like shaking behaviour in rodents, which is hypothesised to engage frontocortical glutamate receptor activation secondary to serotonin2A (5-HT2A) related glutamate release. Challenging this hypothesis, we here investigate whether tolerance to LSD and DOB correlates with frontocortical adaptations of 5-HT2A and/or overall-glutamate binding sites. LSD and DOB (0.025 and 0.25 mg/kg, i.p.) induce a ketanserin-sensitive (0.5 mg/kg, i.p., 30-min pretreatment) increase in shaking behaviour (including head twitches and wet dog shakes), which with repeated application (7× in 4 ds) is undermined by tolerance. Tolerance to DOB, as indexed by DOB-sensitive [(3)H]spiroperidol and DOB induced [(35)S]GTP-gamma-S binding, is accompanied by a frontocortical decrease in 5-HT2A binding sites and 5-HT2 signalling, respectively; glutamate-sensitive [(3)H]glutamate binding sites, in contrast, remain unchanged. As to LSD, 5-HT2 signalling and 5-HT2A binding, respectively, are not or only marginally affected, yet [(3)H]glutamate binding is significantly decreased. Correlation analysis interrelates tolerance to DOB to the reduced 5-HT2A (r=.80) as well as the unchanged [(3)H]glutamate binding sites (r=.84); tolerance to LSD, as opposed, shares variance with the reduction in [(3)H]glutamate binding sites only (r=.86). Given that DOB and LSD both induce tolerance, one correlating with 5-HT2A, the other with glutamate receptor adaptations, it might be inferred that tolerance can arise at either level. That is, if a hallucinogen (like LSD in our study) fails to induce 5-HT2A (down-)regulation, glutamate receptors (activated postsynaptic to 5-HT2A related glutamate release) might instead adapt and thus prevent further overstimulation of the cortex.
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Affiliation(s)
- Tobias Buchborn
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
| | - Helmut Schröder
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
| | - Daniela C Dieterich
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany.
| | - Gisela Grecksch
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
| | - Volker Höllt
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
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