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Redinbaugh MJ, Saalmann YB. Contributions of Basal Ganglia Circuits to Perception, Attention, and Consciousness. J Cogn Neurosci 2024; 36:1620-1642. [PMID: 38695762 PMCID: PMC11223727 DOI: 10.1162/jocn_a_02177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Research into ascending sensory pathways and cortical networks has generated detailed models of perception. These same cortical regions are strongly connected to subcortical structures, such as the basal ganglia (BG), which have been conceptualized as playing key roles in reinforcement learning and action selection. However, because the BG amasses experiential evidence from higher and lower levels of cortical hierarchies, as well as higher-order thalamus, it is well positioned to dynamically influence perception. Here, we review anatomical, functional, and clinical evidence to demonstrate how the BG can influence perceptual processing and conscious states. This depends on the integrative relationship between cortex, BG, and thalamus, which allows contributions to sensory gating, predictive processing, selective attention, and representation of the temporal structure of events.
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Affiliation(s)
| | - Yuri B Saalmann
- University of Wisconsin-Madison
- Wisconsin National Primate Research Center
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2
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Basedow LA, Majić T, Hafiz NJ, Algharably EAE, Kreutz R, Riemer TG. Cognitive functioning associated with acute and subacute effects of classic psychedelics and MDMA - a systematic review and meta-analysis. Sci Rep 2024; 14:14782. [PMID: 38926480 PMCID: PMC11208433 DOI: 10.1038/s41598-024-65391-9] [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: 08/14/2023] [Accepted: 06/19/2024] [Indexed: 06/28/2024] Open
Abstract
Classic psychedelics and MDMA have a colorful history of recreational use, and both have recently been re-evaluated as tools for the treatment of psychiatric disorders. Several studies have been carried out to assess potential long-term effects of a regular use on cognition, delivering distinct results for psychedelics and MDMA. However, to date knowledge is scarce on cognitive performance during acute effects of those substances. In this systematic review and meta-analysis, we investigate how cognitive functioning is affected by psychedelics and MDMA during the acute drug effects and the sub-acute ("afterglow") window. Our quantitative analyses suggest that acute cognitive performance is differentially affected by psychedelics when compared to MDMA: psychedelics impair attention and executive function, whereas MDMA primarily affects memory, leaving executive functions and attention unaffected. Our qualitative analyses reveal that executive functioning and creativity may be increased during a window of at least 24 h after the acute effects of psychedelics have subsided, whereas no such results have been observed for MDMA. Our findings may contribute to inform recommendations on harm reduction for recreational settings and to help fostering differential approaches for the use of psychedelics and MDMA within a therapeutic framework.
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Affiliation(s)
- Lukas A Basedow
- Department of Psychology, Clinical Psychology and Psychotherapy, Philipps-Universität Marburg, Gutenbergstraße 18, 35037, Marburg, Germany.
| | - Tomislav Majić
- Psychedelic Substances Research Group, Department of Psychiatry and Neurosciences, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Department of Psychiatry und Neurosciences, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Nicklas Jakob Hafiz
- Institute for Educational Quality Improvement (IQB), Humboldt-Universität zu Berlin, Berlin, Germany
| | - Engi A E Algharably
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Clinical Pharmacology and Toxicology, Charité Campus Mitte, Charitéplatz 1, 10117, Berlin, Germany
| | - Reinhold Kreutz
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Clinical Pharmacology and Toxicology, Charité Campus Mitte, Charitéplatz 1, 10117, Berlin, Germany
| | - Thomas G Riemer
- Psychedelic Substances Research Group, Department of Psychiatry and Neurosciences, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Clinical Pharmacology and Toxicology, Charité Campus Mitte, Charitéplatz 1, 10117, Berlin, Germany
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3
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Polito V, Liknaitzky P. Is microdosing a placebo? A rapid review of low-dose LSD and psilocybin research. J Psychopharmacol 2024:2698811241254831. [PMID: 38877715 DOI: 10.1177/02698811241254831] [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: 06/16/2024]
Abstract
Some recent research and commentary have suggested that most or all the effects reported by people who microdose psychedelics may be explained by expectations or placebo effects. In this rapid review, we aimed to evaluate the strength of evidence for a placebo explanation of the reported effects of microdosing. We conducted a PubMed search for all studies investigating psychedelic microdosing with controlled doses and a placebo comparator. We identified 19 placebo-controlled microdosing studies and summarised all positive and null findings across this literature. Risk of bias was assessed using the Cochrane risk-of-bias tool for randomised trials. The reviewed papers indicated that microdosing with LSD and psilocybin leads to changes in neurobiology, physiology, subjective experience, affect, and cognition relative to placebo. We evaluate methodological gaps and challenges in microdosing research and suggest eight reasons why current claims that microdosing is predominately a placebo are premature and possibly wrong: (1) there have been only a small number of controlled studies; (2) studies have had small sample sizes; (3) there is evidence of dose-dependent effects; (4) studies have only investigated the effects of a small number of doses; (5) the doses investigated may have been too small; (6) studies have looked only at non-clinical populations; (7) studies so far have been susceptible to selection bias; and (8) the measured impact of expectancy is small. Considering the available evidence, we conclude that it is not yet possible to determine whether microdosing is a placebo.
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Affiliation(s)
- Vince Polito
- School of Psychological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Paul Liknaitzky
- Department of Psychiatry, School of Clinical Sciences, Monash University, Clayton, VIC, Australia
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Australia
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4
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Murray CH, Frohlich J, Haggarty CJ, Tare I, Lee R, de Wit H. Neural complexity is increased after low doses of LSD, but not moderate to high doses of oral THC or methamphetamine. Neuropsychopharmacology 2024; 49:1120-1128. [PMID: 38287172 PMCID: PMC11109226 DOI: 10.1038/s41386-024-01809-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 01/07/2024] [Accepted: 01/17/2024] [Indexed: 01/31/2024]
Abstract
Neural complexity correlates with one's level of consciousness. During coma, anesthesia, and sleep, complexity is reduced. During altered states, including after lysergic acid diethylamide (LSD), complexity is increased. In the present analysis, we examined whether low doses of LSD (13 and 26 µg) were sufficient to increase neural complexity in the absence of altered states of consciousness. In addition, neural complexity was assessed after doses of two other drugs that significantly altered consciousness and mood: delta-9-tetrahydrocannabinol (THC; 7.5 and 15 mg) and methamphetamine (MA; 10 and 20 mg). In three separate studies (N = 73; 21, LSD; 23, THC; 29, MA), healthy volunteers received placebo or drug in a within-subjects design over three laboratory visits. During anticipated peak drug effects, resting state electroencephalography (EEG) recorded Limpel-Ziv complexity and spectral power. LSD, but not THC or MA, dose-dependently increased neural complexity. LSD also reduced delta and theta power. THC reduced, and MA increased, alpha power, primarily in frontal regions. Neural complexity was not associated with any subjective drug effect; however, LSD-induced reductions in delta and theta were associated with elation, and THC-induced reductions in alpha were associated with altered states. These data inform relationships between neural complexity, spectral power, and subjective states, demonstrating that increased neural complexity is not necessary or sufficient for altered states of consciousness. Future studies should address whether greater complexity after low doses of LSD is related to cognitive, behavioral, or therapeutic outcomes, and further examine the role of alpha desynchronization in mediating altered states of consciousness.
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Affiliation(s)
- Conor H Murray
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, Chicago, IL, 60637, USA.
- Department of Psychiatry and Biobehavioral Sciences, University of Los Angeles, California, 760 Westwood Plaza, Los Angeles, CA, 90024, USA.
| | - Joel Frohlich
- Institute for Neuromodulation and Neurotechnology, University of Tübingen, Otfried-Müller-Straße 45, 72076, Tübingen, Germany
- Institute for Advanced Consciousness Studies, Santa Monica, California; 2811 Wilshire Blvd # 510, Santa Monica, CA, 90403, USA
| | - Connor J Haggarty
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, Chicago, IL, 60637, USA
| | - Ilaria Tare
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, Chicago, IL, 60637, USA
| | - Royce Lee
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, Chicago, IL, 60637, USA
| | - Harriet de Wit
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, Chicago, IL, 60637, USA
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Murphy RJ, Muthukumaraswamy S, de Wit H. Microdosing Psychedelics: Current Evidence From Controlled Studies. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2024; 9:500-511. [PMID: 38280630 DOI: 10.1016/j.bpsc.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/06/2024] [Accepted: 01/09/2024] [Indexed: 01/29/2024]
Abstract
Taking regular low doses of psychedelic drugs (microdosing) is a practice that has drawn recent scientific and media attention for its potential psychotherapeutic effects. Yet, controlled studies evaluating this practice have lagged. Here, we review recent evidence focusing on studies that were conducted with rigorous experimental control. Studies conducted under laboratory settings using double-blind placebo-controlled procedures and investigator-supplied drug were compiled. The review includes demographic characteristics of participants and dependent measures such as physiological, behavioral, and subjective effects of the drugs. Review criteria were met by 14 studies, all of which involved acute or repeated low (5-20 μg) doses of lysergic acid diethylamide (LSD). Acute microdoses of LSD dose-dependently altered blood pressure, sleep, neural connectivity, social cognition, mood, and perception of pain and time. Perceptible drug effects were reported at doses of 10 to 20 μg but not 5 μg. No serious adverse effects were reported. Repeated doses of LSD did not alter mood or cognition on any of the measures studied. The findings suggest that low doses of LSD are safe and produce acute behavioral and neural effects in healthy adults. Further studies are warranted to extend these findings to patient samples and to other psychedelic drugs and to investigate microdosing as a potential pharmacological treatment for psychiatric disorders.
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Affiliation(s)
- Robin J Murphy
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Suresh Muthukumaraswamy
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Harriet de Wit
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, Illinois
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Pop IA, Gielens E, Kottmann H, Achterberg P. Exploring the discourses around microdosing psychedelics within the r/microdosing online community. Soc Sci Med 2024; 347:116702. [PMID: 38520826 DOI: 10.1016/j.socscimed.2024.116702] [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: 10/25/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 03/25/2024]
Abstract
In the present contribution, we examine the practice of microdosing psychedelics (microdosing) through textual analysis of the content produced by a dedicated online community, the r/microdosing subreddit. We collected a comprehensive dataset of publicly available submissions from this community and used structural topic modelling to identify and analyse the prevalent topics within the discussions. Through our analysis, we identified 16 distinct topics that mapped into clinical, human enhancement, as well as self-medication narratives. Notably, we found that the majority of discussions revolved around "how to" topics, supporting our argument that such online communities serve as essential information hubs, facilitating the dissemination of practical knowledge related to microdosing practices among the general population. The identified impact of the Covid-19 pandemic on the prevalence of discussion topics suggests that individuals within the online community may perceive microdosing primarily as a means of self-medication during times of heightened stress and uncertainty. Our findings contribute to the field of health sociology and psychedelic research by shedding light on the sociocultural factors influencing healthcare practices, including the role of online communities in facilitating processes of self-medicalization and self-medication.
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Affiliation(s)
- Ioana Andreea Pop
- Tilburg University, Sociology Department, PO BOX 90153, 5000 LE, Tilburg, the Netherlands.
| | - Erwin Gielens
- Tilburg University, Sociology Department, PO BOX 90153, 5000 LE, Tilburg, the Netherlands.
| | - Hannah Kottmann
- Tilburg University, Sociology Department, PO BOX 90153, 5000 LE, Tilburg, the Netherlands.
| | - Peter Achterberg
- Tilburg University, Sociology Department, PO BOX 90153, 5000 LE, Tilburg, the Netherlands.
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Wells A, Muthukumaraswamy APS, Morunga E, Evans W, Cavadino A, Bansal M, Lawrence NJ, Ashley A, Hoeh NR, Sundram F, Applebaum AJ, Parkinson H, Reynolds L. PAM trial protocol: a randomised feasibility study of psychedelic microdosing-assisted meaning-centred psychotherapy in advanced stage cancer patients. Pilot Feasibility Stud 2024; 10:29. [PMID: 38347582 PMCID: PMC10860284 DOI: 10.1186/s40814-024-01449-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 01/12/2024] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND An advanced cancer diagnosis can be associated with a significant profile of distress. Psychedelic compounds have shown clinically significant effects in the treatment of psychological distress in patients with advanced-stage cancer. Given the challenges of delivering timely and effective intervention in the advanced cancer context, it is possible that an alternative, more pragmatic, approach lies in psychedelic 'microdosing'. Microdosing refers to repeated administration of psychedelics in sub-hallucinogenic doses. The purpose of this study is to evaluate the feasibility of conducting a full-scale randomised controlled trial comparing psychedelic microdose-assisted-meaning-centred psychotherapy (PA-MCP) to standard meaning-centred psychotherapy (MCP) in New Zealand indigenous (Māori) and non-indigenous people with advanced cancer and symptoms of anxiety and/or depression. Although MCP is a well-established psychotherapeutic treatment in advanced cancer populations, the potential efficacy and effectiveness of this therapy when delivered alongside a standardised microdose regimen of a psychedelic compound have not been investigated. METHODS Participants with advanced-stage cancer and symptoms of anxiety and/or depression (N = 40; 20 Māori, 20 non-Māori) will be randomised under double-blind conditions to receive 7 sessions of MCP alongside 13 doses of either an LSD microdose (4-20 µg) (PA-MCP) or inactive placebo (placebo-MCP). The feasibility, acceptability, and safety of this intervention and physiological and psychological measures will be recorded at baseline, at each session of MCP, and at a 1-month and 6-month follow-up. DISCUSSION Our findings will evaluate the feasibility, acceptability, and safety of a larger randomised controlled trial and provide an initial indication of the potential benefits of psychedelic microdosing for psychological distress in advanced-stage indigenous and non-indigenous cancer patients. TRIAL REGISTRATION NZCTR, ACTRN12623000478617. Registered 11 May 2023. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=385810&isReview=true .
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Affiliation(s)
- Alesha Wells
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, University of Auckland, 22-30 Park Avenue, Grafton, Auckland, 1023, New Zealand.
| | - A P Suresh Muthukumaraswamy
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Eva Morunga
- Cancer Support Service, Te Toka Tumai Auckland, Auckland City Hospital, Te Whatu Ora2 Park Road, Grafton, Auckland, 1023, New Zealand
- The University of Auckland, 22-30 Park Avenue, Grafton, Auckland, 1023, New Zealand
| | - Will Evans
- Mana Health, 7 Ruskin Street, Parnell, Auckland, 1052, New Zealand
| | - Alana Cavadino
- School of Population Health, The University of Auckland, 22-30 Park Avenue, Grafton, Auckland, 1023, New Zealand
| | - Mahima Bansal
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Nicola J Lawrence
- Department of Oncology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, New Zealand
- Te Pūriri o Te Ora - Regional Cancer and Blood, Te Whatu Ora Te Toka Tumai, 2 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Amanda Ashley
- Te Pūriri o Te Ora - Regional Cancer and Blood, Te Whatu Ora Te Toka Tumai, 2 Park Road, Grafton, Auckland, 1023, New Zealand
- Harbour Cancer and Wellness, 212 Wairau Road, Wairau Valley, Auckland, 0627, New Zealand
| | - Nicholas R Hoeh
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, University of Auckland, 22-30 Park Avenue, Grafton, Auckland, 1023, New Zealand
| | - Frederick Sundram
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, University of Auckland, 22-30 Park Avenue, Grafton, Auckland, 1023, New Zealand
| | - Allison J Applebaum
- Department of Psychiatry and Behavioral Sciences, Memorial Sloan Kettering Cancer Center, 641 Lexington Avenue, 7th Floor, New York, NY, 10022, USA
| | - Hineatua Parkinson
- School of Psychology, University of Auckland, 23 Symonds Street, Auckland Central, 1010, New Zealand
| | - Lisa Reynolds
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, University of Auckland, 22-30 Park Avenue, Grafton, Auckland, 1023, New Zealand
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Harlow AF, Hendricks PS, Leventhal AM, Barrington-Trimis JL. Psychedelic Microdosing among Young Adults from Southern California. J Psychoactive Drugs 2024:1-12. [PMID: 38341607 DOI: 10.1080/02791072.2024.2313684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2024]
Abstract
Despite common depictions in the media, there is little scientific evidence on microdosing psychedelic drugs. We assessed awareness, prevalence, and dosing practices of microdosing psychedelic drugs among young adults 18-22 years old from Southern California (2018-2019). We examined whether sociodemographic factors, personality traits, mental health, or other substance use behaviors were correlated with having ever microdosed. Among 2,396 participants, 293 (12%) had heard of microdosing and 74 (3%) ever microdosed. Among those who had heard of microdosing, 79% correctly defined microdosing as taking an amount of a psychedelic much lower than a standard dose, whereas 15% misperceived microdosing as a standard psychedelic dose. Psilocybin was the most common drug ever microdosed (70%), followed by lysergic acid diethylamide (LSD, 57%). Among those who ever microdosed, ~18% reported using psychoactive doses far higher than would be generally considered a microdose. White race, male/masculine gender identity, bisexual identity, past 6-month other drug use, greater attention deficit/hyperactivity disorder symptoms, mindfulness, and sensation-seeking were positively associated with having ever microdosed in multivariable models. Young adult microdosing merits further attention from scientific and public health professionals to help prevent misperceptions and potential adverse consequences as well as explore its potential therapeutic applications.
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Affiliation(s)
- Alyssa F Harlow
- Department of Population and Public Health Sciences, University of Southern California Keck School of Medicine, Los Angeles, CA, USA
- Institute for Addiction Science, University of Southern California, Los Angeles, CA, USA
| | - Peter S Hendricks
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama School of Medicine, Birmingham, AL, USA
| | - Adam M Leventhal
- Department of Population and Public Health Sciences, University of Southern California Keck School of Medicine, Los Angeles, CA, USA
- Institute for Addiction Science, University of Southern California, Los Angeles, CA, USA
| | - Jessica L Barrington-Trimis
- Department of Population and Public Health Sciences, University of Southern California Keck School of Medicine, Los Angeles, CA, USA
- Institute for Addiction Science, University of Southern California, Los Angeles, CA, USA
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9
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Sadibolova R, DiMarco EK, Jiang A, Maas B, Tatter SB, Laxton A, Kishida KT, Terhune DB. Sub-second and multi-second dopamine dynamics underlie variability in human time perception. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.02.09.24302276. [PMID: 38370629 PMCID: PMC10871373 DOI: 10.1101/2024.02.09.24302276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Timing behaviour and the perception of time are fundamental to cognitive and emotional processes in humans. In non-human model organisms, the neuromodulator dopamine has been associated with variations in timing behaviour, but the connection between variations in dopamine levels and the human experience of time has not been directly assessed. Here, we report how dopamine levels in human striatum, measured with sub-second temporal resolution during awake deep brain stimulation surgery, relate to participants' perceptual judgements of time intervals. Fast, phasic, dopaminergic signals were associated with underestimation of temporal intervals, whereas slower, tonic, decreases in dopamine were associated with poorer temporal precision. Our findings suggest a delicate and complex role for the dynamics and tone of dopaminergic signals in the conscious experience of time in humans.
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Affiliation(s)
- Renata Sadibolova
- Department of Psychology, Goldsmiths, University of London; London SE14 6NW, UK
- Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King’s College London; London SE5 8AB, UK
- School of Psychology, University of Roehampton; London SW15 4JD, UK
| | - Emily K. DiMarco
- Neuroscience Graduate Program, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
- Department of Translational Neuroscience, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
| | - Angela Jiang
- Department of Translational Neuroscience, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
| | - Benjamin Maas
- Department of Translational Neuroscience, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
- Virginia Tech – Wake Forest University School of Biomedical Engineering and Sciences, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
- Department of Biomedical Engineering, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
| | - Stephen B. Tatter
- Department of Neurosurgery, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
| | - Adrian Laxton
- Department of Neurosurgery, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
| | - Kenneth T. Kishida
- Neuroscience Graduate Program, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
- Department of Translational Neuroscience, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
- Virginia Tech – Wake Forest University School of Biomedical Engineering and Sciences, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
- Department of Biomedical Engineering, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
- Department of Neurosurgery, Wake Forest School of Medicine; Winston-Salem, NC, 27157, USA
| | - Devin B. Terhune
- Department of Psychology, Goldsmiths, University of London; London SE14 6NW, UK
- Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King’s College London; London SE5 8AB, UK
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10
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Petranker R, Anderson T, Fewster EC, Aberman Y, Hazan M, Gaffrey M, Seli P. Keeping the promise: a critique of the current state of microdosing research. Front Psychiatry 2024; 15:1217102. [PMID: 38374976 PMCID: PMC10875010 DOI: 10.3389/fpsyt.2024.1217102] [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: 05/04/2023] [Accepted: 01/05/2024] [Indexed: 02/21/2024] Open
Abstract
Introduction The practice of taking small, sub-hallucinogenic doses of psychedelics, known as microdosing, has exploded in popularity over the last decade. Users claim benefits ranging from improved mood and enhanced creativity to an increased sense of meaning and connectedness in life. While research on microdosing is still lagging behind the shift in public opinion, several papers have been published in the last five years which attempted to assess the effects of microdosing. Methods This review paper aimed to critically analyze the research practices used in the recent wave of microdosing research: We reviewed 15 papers published before the closing date of this review in March 2022. Results Our review concludes that it is premature to draw any conclusions about the efficacy or safety of microdosing since the research quality cannot be considered confirmatory. Discussion We propose some potential causes for the current state of the literature and some suggestions for how these causes may be ameliorated.
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Affiliation(s)
- Rotem Petranker
- Department of Psychology, Neuroscience and Behaviour, Hamilton, ON, Canada
| | - Thomas Anderson
- Department of Psychology, University of Toronto, Toronto, ON, Canada
| | | | | | - Marik Hazan
- Independent Researcher, New York, NY, United States
| | - Michael Gaffrey
- Department of Psychology and Neuroscience, Duke University, Durham, NC, United States
| | - Paul Seli
- Department of Psychology and Neuroscience, Duke University, Durham, NC, United States
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11
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Madrid-Gambin F, Fabregat-Safont D, Gomez-Gomez A, Olesti E, Mason NL, Ramaekers JG, Pozo OJ. Present and future of metabolic and metabolomics studies focused on classical psychedelics in humans. Biomed Pharmacother 2023; 169:115775. [PMID: 37944438 DOI: 10.1016/j.biopha.2023.115775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/16/2023] [Accepted: 10/20/2023] [Indexed: 11/12/2023] Open
Abstract
Psychedelics are classical hallucinogen drugs that induce a marked altered state of consciousness. In recent years, there has been renewed attention to the possible use of classical psychedelics for the treatment of certain mental health disorders. However, further investigation to better understand their biological effects in humans, their mechanism of action, and their metabolism in humans is needed when considering the development of future novel therapeutic approaches. Both metabolic and metabolomics studies may help for these purposes. On one hand, metabolic studies aim to determine the main metabolites of the drug. On the other hand, the application of metabolomics in human psychedelics studies can help to further understand the biological processes underlying the psychedelic state and the mechanisms of action underlying their therapeutic potential. This review presents the state of the art of metabolic and metabolomic studies after lysergic acid diethylamide (LSD), mescaline, N,N-dimethyltryptamine (DMT) and β-carboline alkaloids (ayahuasca brew), 5-methoxy-DMT and psilocybin administrations in humans. We first describe the characteristics of the published research. Afterward, we reviewed the main results obtained by both metabolic and metabolomics (if available) studies in classical psychedelics and we found out that metabolic and metabolomics studies in psychedelics progress at two different speeds. Thus, whereas the main metabolites for classical psychedelics have been robustly established, the main metabolic alterations induced by psychedelics need to be explored. The integration of metabolomics and pharmacokinetics for investigating the molecular interaction between psychedelics and multiple targets may open new avenues in understanding the therapeutic role of psychedelics.
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Affiliation(s)
- Francisco Madrid-Gambin
- Applied Metabolomics Research Group, Hospital del Mar Research Institute, 08003 Barcelona, Spain.
| | - David Fabregat-Safont
- Applied Metabolomics Research Group, Hospital del Mar Research Institute, 08003 Barcelona, Spain; Environmental and Public Health Analytical Chemistry, Research Institute for Pesticides and Water, University Jaume I, 12071 Castelló, Spain
| | - Alex Gomez-Gomez
- Applied Metabolomics Research Group, Hospital del Mar Research Institute, 08003 Barcelona, Spain; CERBA Internacional, Chromatography Department, 08203 Sabadell, Spain
| | - Eulàlia Olesti
- Department of Clinical Pharmacology, Area Medicament, Hospital Clinic of Barcelona, 08036 Barcelona, Spain; Clinical Pharmacology, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Natasha L Mason
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, 6200 MD Maastricht, the Netherlands
| | - Johannes G Ramaekers
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, 6200 MD Maastricht, the Netherlands
| | - Oscar J Pozo
- Applied Metabolomics Research Group, Hospital del Mar Research Institute, 08003 Barcelona, Spain.
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Onofrj M, Russo M, Delli Pizzi S, De Gregorio D, Inserra A, Gobbi G, Sensi SL. The central role of the Thalamus in psychosis, lessons from neurodegenerative diseases and psychedelics. Transl Psychiatry 2023; 13:384. [PMID: 38092757 PMCID: PMC10719401 DOI: 10.1038/s41398-023-02691-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/06/2023] [Accepted: 11/27/2023] [Indexed: 12/17/2023] Open
Abstract
The PD-DLB psychosis complex found in Parkinson's disease (PD) and Dementia with Lewy Bodies (DLB) includes hallucinations, Somatic Symptom/Functional Disorders, and delusions. These disorders exhibit similar presentation patterns and progression. Mechanisms at the root of these symptoms also share similarities with processes promoting altered states of consciousness found in Rapid Eye Movement sleep, psychiatric disorders, or the intake of psychedelic compounds. We propose that these mechanisms find a crucial driver and trigger in the dysregulated activity of high-order thalamic nuclei set in motion by ThalamoCortical Dysrhythmia (TCD). TCD generates the loss of finely tuned cortico-cortical modulations promoted by the thalamus and unleashes the aberrant activity of the Default Mode Network (DMN). TCD moves in parallel with altered thalamic filtering of external and internal information. The process produces an input overload to the cortex, thereby exacerbating DMN decoupling from task-positive networks. These phenomena alter the brain metastability, creating dreamlike, dissociative, or altered states of consciousness. In support of this hypothesis, mind-altering psychedelic drugs also modulate thalamic-cortical pathways. Understanding the pathophysiological background of these conditions provides a conceptual bridge between neurology and psychiatry, thereby helping to generate a promising and converging area of investigation and therapeutic efforts.
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Affiliation(s)
- Marco Onofrj
- Behavioral Neurology and Molecular Neurology Units, Center for Advanced Studies and Technology - CAST, Institute for Advanced Biomedical Technology-ITAB University G. d'Annunzio of Chieti-Pescara, Chieti, Italy.
- Department of Neuroscience, Imaging, and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy.
| | - Mirella Russo
- Behavioral Neurology and Molecular Neurology Units, Center for Advanced Studies and Technology - CAST, Institute for Advanced Biomedical Technology-ITAB University G. d'Annunzio of Chieti-Pescara, Chieti, Italy
- Department of Neuroscience, Imaging, and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy
| | - Stefano Delli Pizzi
- Behavioral Neurology and Molecular Neurology Units, Center for Advanced Studies and Technology - CAST, Institute for Advanced Biomedical Technology-ITAB University G. d'Annunzio of Chieti-Pescara, Chieti, Italy
- Department of Neuroscience, Imaging, and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy
| | - Danilo De Gregorio
- Division of Neuroscience, Vita-Salute San Raffaele University, Milan, Italy
| | - Antonio Inserra
- Neurobiological Psychiatry Unit, McGill University, Montreal, QC, Canada
| | - Gabriella Gobbi
- Neurobiological Psychiatry Unit, McGill University, Montreal, QC, Canada
| | - Stefano L Sensi
- Behavioral Neurology and Molecular Neurology Units, Center for Advanced Studies and Technology - CAST, Institute for Advanced Biomedical Technology-ITAB University G. d'Annunzio of Chieti-Pescara, Chieti, Italy.
- Department of Neuroscience, Imaging, and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy.
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Wsół A. Cardiovascular safety of psychedelic medicine: current status and future directions. Pharmacol Rep 2023; 75:1362-1380. [PMID: 37874530 PMCID: PMC10661823 DOI: 10.1007/s43440-023-00539-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/02/2023] [Accepted: 10/02/2023] [Indexed: 10/25/2023]
Abstract
Psychedelics are powerful psychoactive substances that alter perception and mood processes. Their effectiveness in the treatment of psychiatric diseases was known before their prohibition. An increasing number of recent studies, due to the indisputable resurgence of serotonergic hallucinogens, have shown their efficacy in alleviating depression, anxiety, substance abuse therapies, and existential distress treatment in patients facing life-threatening illness. Psychedelics are generally considered to be physiologically safe with low toxicity and low addictive potential. However, their agonism at serotonergic receptors should be considered in the context of possible serotonin-related cardiotoxicity (5-HT2A/2B and 5-HT4 receptors), influence on platelet aggregation (5-HT2A receptor), and their proarrhythmic potential. The use of psychedelics has also been associated with significant sympathomimetic effects in both experimental and clinical studies. Therefore, the present review aims to provide a critical discussion of the cardiovascular safety of psilocybin, d-lysergic acid diethylamide (LSD), N,N-dimethyltryptamine, ayahuasca, and mescaline, based on the results of experimental research and clinical trials in humans. Experimental studies provide inconsistent information on the potential cardiovascular effects and toxicity of psychedelics. Data from clinical trials point to the relative cardiovascular safety of psychedelic-assisted therapies in the population of "healthy" volunteers. However, there is insufficient evidence from therapies carried out with microdoses of psychedelics, and there is still a lack of data on the safety of psychedelics in the population of patients with cardiovascular disease. Therefore, the exact determination of the cardiovascular safety of psychedelic therapies (especially long-term therapies) requires further research.
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Affiliation(s)
- Agnieszka Wsół
- Chair and Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1B, 02-097, Warsaw, Poland.
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Murphy RJ, Sumner R, Evans W, Ponton R, Ram S, Godfrey K, Forsyth A, Cavadino A, Krishnamurthy Naga V, Smith T, Hoeh NR, Menkes DB, Muthukumaraswamy S. Acute Mood-Elevating Properties of Microdosed Lysergic Acid Diethylamide in Healthy Volunteers: A Home-Administered Randomized Controlled Trial. Biol Psychiatry 2023; 94:511-521. [PMID: 36997080 DOI: 10.1016/j.biopsych.2023.03.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 04/01/2023]
Abstract
BACKGROUND Microdosing psychedelic drugs is a widespread social phenomenon with diverse benefits claimed for mood and cognition. Randomized controlled trials have failed to support these claims, but the laboratory-based dosing in trials conducted to date may have limited ecological validity. METHODS Healthy male volunteers were randomized into lysergic acid diethylamide (LSD) (n = 40) and placebo (n = 40) groups and received 14 doses of either 10 μg LSD or an inactive placebo every 3 days for 6 weeks. First doses were given in a supervised laboratory setting, with other doses self-administered in a naturalistic setting. Results of safety data, blinding, daily questionnaires, expectancy, and pre-/postintervention psychometrics and cognitive tasks are presented here. RESULTS The most notable reported adverse event was treatment-related anxiety, which prompted the withdrawal of 4 participants from the LSD group. Daily questionnaires showed credible evidence (>99% posterior probability) of improved ratings of creativity, connectedness, energy, happiness, irritability, and wellness on dose days compared with nondose days, and these effects remained when controlling for preintervention expectancy. No questionnaire or cognitive task showed a credible change between baseline and 6-week assessment time points. CONCLUSIONS Microdosing LSD appears to be relatively safe in healthy adult men, notwithstanding a risk of anxiety. While microdosing elicited transient increases in scales associated with mood-elevating effects, it was not sufficient to promote enduring changes to overall mood or cognition in healthy adults. Future microdosing trials in clinical populations will require the use of active placebos to control for placebo effects and dose titration to adjust for interindividual variability in drug response.
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Affiliation(s)
- Robin J Murphy
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
| | - Rachael Sumner
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | | | - Rhys Ponton
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Sanya Ram
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Kate Godfrey
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; Centre for Psychedelic Research, Department of Psychiatry, Imperial College London, London, England, UK
| | - Anna Forsyth
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Alana Cavadino
- Epidemiology and Biostatistics, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Venkat Krishnamurthy Naga
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | | | - Nicholas R Hoeh
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - David B Menkes
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Suresh Muthukumaraswamy
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
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15
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Tagen M, Mantuani D, van Heerden L, Holstein A, Klumpers LE, Knowles R. The risk of chronic psychedelic and MDMA microdosing for valvular heart disease. J Psychopharmacol 2023; 37:876-890. [PMID: 37572027 DOI: 10.1177/02698811231190865] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/14/2023]
Abstract
Psychedelic microdosing is the practice of taking very low doses of psychedelic substances, typically over a longer period of time. The long-term safety of chronic microdosing is relatively uncharacterized, but valvular heart disease (VHD) has been proposed as a potential risk due to activation of the serotonin 5-HT2B receptor. However, this risk has not yet been comprehensively assessed. This analysis searched for all relevant in vitro, animal, and clinical studies related to the VHD risk of lysergic acid diethylamide (LSD), psilocybin, mescaline, N,N-dimethyltryptamine (DMT), and the non-psychedelic 3,4-methylenedioxymethamphetamine (MDMA). All five compounds and some metabolites could bind to the 5-HT2B receptor with potency equal to or greater than that of the 5-HT2A receptor, the primary target of psychedelics. All compounds were partial agonists at the 5-HT2B receptor with the exception of mescaline, which could not be adequately assessed due to low potency. Safety margins relative to the maximum plasma concentrations from typical microdoses were greater than known valvulopathogens, but not without potential risk. No animal or clinical studies appropriately designed to evaluate VHD risk were found for the four psychedelics. However, there is some clinical evidence that chronic ingestion of full doses of MDMA is associated with VHD. We conclude that VHD is a potential risk with chronic psychedelic microdosing, but further studies are necessary to better define this risk.
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Affiliation(s)
| | - Daniel Mantuani
- Delos Psyche Research Group, Mountain View, CA, USA
- Delos Therapeutics, Mountain View, CA, USA
| | - Liron van Heerden
- Delos Psyche Research Group, Mountain View, CA, USA
- Delos Therapeutics, Mountain View, CA, USA
| | - Alex Holstein
- Delos Psyche Research Group, Mountain View, CA, USA
- Delos Therapeutics, Mountain View, CA, USA
| | - Linda E Klumpers
- Verdient Science LLC, Englewood, CO, USA
- Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - Richard Knowles
- Delos Psyche Research Group, Mountain View, CA, USA
- Delos Therapeutics, Mountain View, CA, USA
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16
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Jaster AM, González-Maeso J. Mechanisms and molecular targets surrounding the potential therapeutic effects of psychedelics. Mol Psychiatry 2023; 28:3595-3612. [PMID: 37759040 DOI: 10.1038/s41380-023-02274-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023]
Abstract
Psychedelics, also known as classical hallucinogens, have been investigated for decades due to their potential therapeutic effects in the treatment of neuropsychiatric and substance use disorders. The results from clinical trials have shown promise for the use of psychedelics to alleviate symptoms of depression and anxiety, as well as to promote substantial decreases in the use of nicotine and alcohol. While these studies provide compelling evidence for the powerful subjective experience and prolonged therapeutic adaptations, the underlying molecular reasons for these robust and clinically meaningful improvements are still poorly understood. Preclinical studies assessing the targets and circuitry of the post-acute effects of classical psychedelics are ongoing. Current literature is split between a serotonin 5-HT2A receptor (5-HT2AR)-dependent or -independent signaling pathway, as researchers are attempting to harness the mechanisms behind the sustained post-acute therapeutically relevant effects. A combination of molecular, behavioral, and genetic techniques in neuropharmacology has begun to show promise for elucidating these mechanisms. As the field progresses, increasing evidence points towards the importance of the subjective experience induced by psychedelic-assisted therapy, but without further cross validation between clinical and preclinical research, the why behind the experience and its translational validity may be lost.
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Affiliation(s)
- Alaina M Jaster
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA
| | - Javier González-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA.
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17
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Szigeti B, Nutt D, Carhart-Harris R, Erritzoe D. The difference between 'placebo group' and 'placebo control': a case study in psychedelic microdosing. Sci Rep 2023; 13:12107. [PMID: 37495637 PMCID: PMC10371989 DOI: 10.1038/s41598-023-34938-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 05/10/2023] [Indexed: 07/28/2023] Open
Abstract
In medical trials, 'blinding' ensures the equal distribution of expectancy effects between treatment arms in theory; however, blinding often fails in practice. We use computational modelling to show how weak blinding, combined with positive treatment expectancy, can lead to an uneven distribution of expectancy effects. We call this 'activated expectancy bias' (AEB) and show that AEB can inflate estimates of treatment effects and create false positive findings. To counteract AEB, we introduce the Correct Guess Rate Curve (CGRC), a statistical tool that can estimate the outcome of a perfectly blinded trial based on data from an imperfectly blinded trial. To demonstrate the impact of AEB and the utility of the CGRC on empirical data, we re-analyzed the 'self-blinding psychedelic microdose trial' dataset. Results suggest that observed placebo-microdose differences are susceptible to AEB and are at risk of being false positive findings, hence, we argue that microdosing can be understood as active placebo. These results highlight the important difference between 'trials with a placebo-control group', i.e., when a placebo control group is formally present, and 'placebo-controlled trials', where patients are genuinely blind. We also present a new blinding integrity assessment tool that is compatible with CGRC and recommend its adoption.
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Affiliation(s)
- Balázs Szigeti
- Centre for Psychedelic Research, Imperial College London, London, UK.
| | - David Nutt
- Centre for Psychedelic Research, Imperial College London, London, UK
| | - Robin Carhart-Harris
- Psychedelics Division, Neuroscape, Department of Neurology, University of California San Francisco, San Francisco, USA
| | - David Erritzoe
- Centre for Psychedelic Research, Imperial College London, London, UK
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18
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Michael P, Luke D, Robinson O. An encounter with the self: A thematic and content analysis of the DMT experience from a naturalistic field study. Front Psychol 2023; 14:1083356. [PMID: 37051610 PMCID: PMC10083325 DOI: 10.3389/fpsyg.2023.1083356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/22/2023] [Indexed: 03/28/2023] Open
Abstract
IntroductionN,N-Dimethyltryptamine (DMT) is an endogenous serotonergic psychedelic capable of producing radical shifts in an experience that have significant implications for consciousness and its neural correlates, especially given the “disconnected consciousness” suggested by the “breakthrough” DMT state. Its increasing usage and clinical trial indicate the growing importance of a thorough elucidation of the experience's qualitative content, over and above the phenomenological structure. This is particularly in light of the intensely pervasive effects of DMT occasions in all dimensions of the self, which are often ontologically challenging yet potentially transformative.MethodsThis is the second report on the first naturalistic field study of DMT use exploring its qualitative analysis. Screened, healthy, anonymized, and experienced DMT users were observed during their non-clinical use of the drug at home (40–75-mg inhaled). In-depth semi-structured interviews, inspired by the micro-phenomenological technique, were employed immediately after their experience. This study reports on the thematic and content analysis of one major domain of the breakthrough experiences elicited, the “self”; where analyses of the “other” were previously reported. A total of 36 post-DMT experience interviews with mostly Caucasian (83%) men (eight women) of a mean of 37 years were predominantly inductively coded.ResultsInvariably, profound and highly intense experiences occurred. The first overarching category comprised the onset of effects, encompassing super-ordinate themes including sensory, emotion and body, and space-time shifts; the second category comprised bodily effects, encompassing themes including pleasurable, neutral/both, and uncomfortable; the third category comprised the sensorial effects, encompassing open-eye, visual, and cross-modal and other; the fourth comprised the psychological effects, encompassing memory and language, awareness and sense of self, and time distortions; and the fifth comprised the emotional effects, encompassing positive, neither/both, and challenging experiences. Many further subthemes also illuminate the rich content of the DMT experience.DiscussionThe present study provides a systematic and nuanced analysis of the content of the breakthrough DMT state pertaining to one's personal and self-referential experiences of the body, senses, psychology, and emotions. The resonances both with previous DMT studies and other types of extraordinary experiences, such as the alien abduction, shamanic and near-death experiences, are also elaborated upon. Putative neural mechanisms and their promise as a psychotherapeutic agent, especially owing to deep emotional impact, are discussed.
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Affiliation(s)
- Pascal Michael
- Centre for Mental Health, School of Human Sciences, Old Royal Naval College, University of Greenwich, London, United Kingdom
| | - David Luke
- Centre for Mental Health, School of Human Sciences, Old Royal Naval College, University of Greenwich, London, United Kingdom
- Department of Brain Sciences, Faculty of Medicine, Centre for Psychedelic Research, Imperial College London, London, United Kingdom
| | - Oliver Robinson
- Centre for Mental Health, School of Human Sciences, Old Royal Naval College, University of Greenwich, London, United Kingdom
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19
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Ryan RS, Copello A, Fox AP. Experiences of microdosing psychedelics in an attempt to support wellbeing and mental health. BMC Psychiatry 2023; 23:160. [PMID: 36918852 PMCID: PMC10012542 DOI: 10.1186/s12888-023-04628-9] [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] [Received: 09/18/2022] [Accepted: 02/22/2023] [Indexed: 03/15/2023] Open
Abstract
BACKGROUND Microdosing psychedelic drugs is a growing phenomenon, but little is known about the experiences surrounding this. Research broadly suggests that people may use psychedelics in an attempt to self-medicate for mental health and wellbeing. However, the precise details, rationale and meaning of such attempts remains unclear, and would benefit from clarification, using tailored experiential methods. This research therefore aimed to explore the way that users make sense of microdosing psychedelics, with a particular focus on the experience of any perceived mental health or wellbeing changes. METHOD Participants were recruited via websites and online forums. An internet text-based, semi-structured interview was conducted anonymously with 13 participants regarding their experiences of microdosing psychedelic drugs. Interpretive Phenomenological Analysis was used to analyse the transcripts. RESULTS Three superordinate themes were identified through the interviews: 1) Seeking a solution: Agency and rationale; 2) Microdosers as scientists; 3) Catalysing desirable and beneficial effects. CONCLUSIONS All participants approached microdosing methodically and with purpose. Participants reported that they had experienced beneficial effects of microdosing on their mental health, alongside cognitive, physical and social changes. By microdosing, participants reported that they had supported their own mental health and wellbeing, with microdosing described as a catalyst to achieving their aims in this area. This study provided additional knowledge and understanding of the experience, rationale and personal meaning of the microdosing phenomenon which can be used to inform future investigations in the areas of psychedelic use and mental health.
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Affiliation(s)
- Rebecca S Ryan
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Alex Copello
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Andrew P Fox
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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20
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DiMarco E, Sadibolova R, Jiang A, Liebenow B, Jones RE, Ul Haq I, Siddiqui MS, Terhune DB, Kishida KT. Time perception reflects individual differences in motor and non-motor symptoms of Parkinson's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.02.530411. [PMID: 36909605 PMCID: PMC10002735 DOI: 10.1101/2023.03.02.530411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Dopaminergic signaling in the striatum has been shown to play a critical role in the perception of time. Decreasing striatal dopamine efficacy is at the core of Parkinson's disease (PD) motor symptoms and changes in dopaminergic action have been associated with many comorbid non-motor symptoms in PD. We hypothesize that patients with PD perceive time differently and in accordance with their specific comorbid non-motor symptoms and clinical state. We recruited patients with PD and compared individual differences in patients' clinical features with their ability to judge millisecond to second intervals of time (500ms-1100ms) while on or off their prescribed dopaminergic medications. We show that individual differences in comorbid non-motor symptoms, PD duration, and prescribed dopaminergic pharmacotherapeutics account for individual differences in time perception performance. We report that comorbid impulse control disorder is associated with temporal overestimation; depression is associated with decreased temporal accuracy; and PD disease duration and prescribed levodopa monotherapy are associated with reduced temporal precision and accuracy. Observed differences in time perception are consistent with hypothesized dopaminergic mechanisms thought to underlie the respective motor and non-motor symptoms in PD, but also raise questions about specific dopaminergic mechanisms. In future work, time perception tasks like the one used here, may provide translational or reverse translational utility in investigations aimed at disentangling neural and cognitive systems underlying PD symptom etiology. One Sentence Summary Quantitative characterization of time perception behavior reflects individual differences in Parkinson's disease motor and non-motor symptom clinical presentation that are consistent with hypothesized neural and cognitive mechanisms.
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Wehrman JJ, Chung CC, Sanders R. Anaesthetics and time perception: A review. Q J Exp Psychol (Hove) 2023:17470218221144614. [PMID: 36453756 DOI: 10.1177/17470218221144614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Consciousness requires subjective experience in the "now." Establishing "now," however, necessitates temporal processing. In the current article, we review one method of altering consciousness, anaesthetic drug administration, and its effects on perceived duration. We searched PubMed, PsycInfo, and ScienceDirect databases, and article reference sections, for combinations of anaesthetic drugs and time perception tasks, finding a total of 36 articles which met our inclusion criteria. We categorised these articles with regard to whether they altered the felt passage of time, short or long interval timing, or were motor timing tasks. We found that various drugs alter the perceived passage of time; ketamine makes time subjectively slow down while GABAergic drugs make time subjectively speed up. At a short interval there is little established evidence of a shift in time perception, though temporal estimates appear more variable. Similarly, when asked to use time to optimise responses (i.e., in motor timing tasks), various anaesthetic agents make timing more variable. Longer durations are estimated as lasting longer than their objective duration, though there is some variation across articles in this regard. We conclude by proposing further experiments to examine time perception under altered states of consciousness and ask whether it is possible to perceive the passage of time of events which do not necessarily reach the level of conscious perception. The variety of methods used raises the need for more systematic investigations of time perception under anaesthesia. We encourage future investigations into the overlap of consciousness and time perception to advance both fields.
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Affiliation(s)
| | - Clara C Chung
- Royal Prince Alfred Hospital, Sydney, NSW, Australia
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22
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Glazer J, Murray CH, Nusslock R, Lee R, de Wit H. Low doses of lysergic acid diethylamide (LSD) increase reward-related brain activity. Neuropsychopharmacology 2023; 48:418-426. [PMID: 36284231 PMCID: PMC9751270 DOI: 10.1038/s41386-022-01479-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 12/26/2022]
Abstract
Renewed interest in classic psychedelics as treatments for psychiatric disorders warrants a deeper understanding of their neural mechanisms. Single, high doses of psychedelic drugs have shown promise in treating depressive disorders, perhaps by reversing deficits in reward processing in the brain. In addition, there are anecdotal reports that repeated ingestion of low doses of LSD, or "microdosing", improve mood, cognition, and feelings of wellbeing. However, the effects of low doses of classic psychedelics on reward processing have not been studied. The current study examined the effects of two single, low doses of LSD compared to placebo on measures of reward processing. Eighteen healthy adults completed three sessions in which they received placebo (LSD-0), 13 μg LSD (LSD-13) and 26 μg LSD (LSD-26) in a within-subject, double-blind design. Neural activity was recorded while participants completed the electrophysiological monetary incentive delay task. Event-related potentials were measured during feedback processing (Reward-Positivity: RewP, Feedback-P3: FB-P3, and Late-Positive Potential: LPP). Compared to placebo, LSD-13 increased RewP and LPP amplitudes for reward (vs. neutral) feedback, and LSD-13 and LSD-26 increased FB-P3 amplitudes for positive (vs. negative) feedback. These effects were unassociated with most subjective measures of drug effects. Thus, single, low doses of LSD (vs. placebo) increased three reward-related ERP components reflecting increased hedonic (RewP), motivational (FB-P3), and affective processing of feedback (LPP). These results constitute the first evidence that low doses of LSD increase reward-related brain activity in humans. These findings may have important implications for the treatment of depressive disorders.
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Affiliation(s)
- James Glazer
- Department of Psychology, Northwestern University, 2029 Sheridan Road Evanston, Chicago, IL, 60208, USA
| | - Conor H Murray
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, Chicago, IL, 60637, USA
| | - Robin Nusslock
- Department of Psychology, Northwestern University, 2029 Sheridan Road Evanston, Chicago, IL, 60208, USA
| | - Royce Lee
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, Chicago, IL, 60637, USA
| | - Harriet de Wit
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, Chicago, IL, 60637, USA.
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Kanen JW, Luo Q, Rostami Kandroodi M, Cardinal RN, Robbins TW, Nutt DJ, Carhart-Harris RL, den Ouden HEM. Effect of lysergic acid diethylamide (LSD) on reinforcement learning in humans. Psychol Med 2022; 53:1-12. [PMID: 36411719 PMCID: PMC10600934 DOI: 10.1017/s0033291722002963] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 08/28/2022] [Accepted: 08/31/2022] [Indexed: 11/23/2022]
Abstract
BACKGROUND The non-selective serotonin 2A (5-HT2A) receptor agonist lysergic acid diethylamide (LSD) holds promise as a treatment for some psychiatric disorders. Psychedelic drugs such as LSD have been suggested to have therapeutic actions through their effects on learning. The behavioural effects of LSD in humans, however, remain incompletely understood. Here we examined how LSD affects probabilistic reversal learning (PRL) in healthy humans. METHODS Healthy volunteers received intravenous LSD (75 μg in 10 mL saline) or placebo (10 mL saline) in a within-subjects design and completed a PRL task. Participants had to learn through trial and error which of three stimuli was rewarded most of the time, and these contingencies switched in a reversal phase. Computational models of reinforcement learning (RL) were fitted to the behavioural data to assess how LSD affected the updating ('learning rates') and deployment of value representations ('reinforcement sensitivity') during choice, as well as 'stimulus stickiness' (choice repetition irrespective of reinforcement history). RESULTS Raw data measures assessing sensitivity to immediate feedback ('win-stay' and 'lose-shift' probabilities) were unaffected, whereas LSD increased the impact of the strength of initial learning on perseveration. Computational modelling revealed that the most pronounced effect of LSD was the enhancement of the reward learning rate. The punishment learning rate was also elevated. Stimulus stickiness was decreased by LSD, reflecting heightened exploration. Reinforcement sensitivity differed by phase. CONCLUSIONS Increased RL rates suggest LSD induced a state of heightened plasticity. These results indicate a potential mechanism through which revision of maladaptive associations could occur in the clinical application of LSD.
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Affiliation(s)
- Jonathan W. Kanen
- Department of Psychology, University of Cambridge, Cambridge, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Qiang Luo
- National Clinical Research Center for Aging and Medicine at Huashan Hospital, State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science and Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, 200433, China
- Center for Computational Psychiatry, Ministry of Education-Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence, Human Phenome Institute, Fudan University, Shanghai, 200032, China
- Shanghai Key Laboratory of Mental Health and Psychological Crisis Intervention, School of Psychology and Cognitive Science, East China Normal University, Shanghai, 200241, China
| | - Mojtaba Rostami Kandroodi
- Department of Cognitive Science and Artificial Intelligence, Tilburg University, Tilburg, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Rudolf N. Cardinal
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Department of Psychiatry, University of Cambridge, Cambridge, UK
- Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK
| | - Trevor W. Robbins
- Department of Psychology, University of Cambridge, Cambridge, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - David J. Nutt
- Department of Brain Sciences, Centre for Psychedelic Research, Imperial College London, London, UK
| | - Robin L. Carhart-Harris
- Neuroscape Psychedelics Division, University of California San Francisco, San Francisco, California, USA
| | - Hanneke E. M. den Ouden
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
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24
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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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25
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Kaypak AC, Raz A. Macrodosing to microdosing with psychedelics: Clinical, social, and cultural perspectives. Transcult Psychiatry 2022; 59:665-674. [PMID: 36031848 DOI: 10.1177/13634615221119386] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
To date, the clinical and scientific literature has best documented the effects of classical psychedelics, such as lysergic acid diethylamide (LSD), psilocybin, and dimethyltryptamine (DMT), in typical quantities most often associated with macrodosing. More recently, however, microdosing with psychedelics has emerged as a social trend and nascent therapeutic intervention. This variation in psychedelic practice refers to repeat, intermittent ingestion of less-than-macrodose amounts that do not cause the effects associated with full-blown "trips". Microdosing paves the road to incorporating psychedelic drugs into a daily routine while maintaining, or even improving, cognitive and mental function. Unlike macrodosing with psychedelics, the influence of microdosing remains mostly unexplored. And yet, despite the paucity of formal studies, many informal accounts propose that microdosing plays an important role as both a therapeutic intervention (e.g., in mental disorders) and enhancement tool (e.g., recreationally-to boost creativity, improve cognition, and drive personal growth). In response to this relatively new practice, we provide an integrative synthesis of the clinical, social, and cultural dimensions of microdosing. We describe some of the overarching context that explains why this practice is increasingly in vogue, unpack potential benefits and risks, and comment on sociocultural implications. In addition, this article considers the effects that macro- and microdoses have on behavior and psychopathology in light of their dosage characteristics and contexts of use.
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Affiliation(s)
- Ayse Ceren Kaypak
- Lady Davis Institute for Medical Research, 293290Institute for Community and Family Psychiatry, Jewish General Hospital, Montreal, QC, Canada.,Department of Psychiatry, 64050Marmara University School of Medicine, Istanbul, Turkey
| | - Amir Raz
- Lady Davis Institute for Medical Research, 293290Institute for Community and Family Psychiatry, Jewish General Hospital, Montreal, QC, Canada.,Departments of Psychiatry, Psychology, and Neurology & Neurosurgery, 5620McGill University, Montreal, QC, Canada.,Montreal Neurological Institute, 5620McGill University, Montreal, QC, Canada.,Institute for Interdisciplinary Brain and Behavioral Sciences, 6226Chapman University, Irvine, CA, USA
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26
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Rosica K, Suchet M. Coda: Widening the Scope of Psychoanalysis. PSYCHOANALYTIC DIALOGUES 2022. [DOI: 10.1080/10481885.2022.2107856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Karen Rosica
- Denver Psychoanalytic Institute, Denver, Colorado, USA
| | - Melanie Suchet
- NYU Postdoctoral Program in Psychotherapy and Psychoanalysis, New York, New York, USA
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27
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Natural language signatures of psilocybin microdosing. Psychopharmacology (Berl) 2022; 239:2841-2852. [PMID: 35676541 DOI: 10.1007/s00213-022-06170-0] [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: 02/28/2022] [Accepted: 05/26/2022] [Indexed: 10/18/2022]
Abstract
RATIONALE Serotonergic psychedelics are being studied as novel treatments for mental health disorders and as facilitators of improved well-being, mental function, and creativity. Recent studies have found mixed results concerning the effects of low doses of psychedelics ("microdosing") on these domains. However, microdosing is generally investigated using instruments designed to assess larger doses of psychedelics, which might lack sensitivity and specificity for this purpose. OBJECTIVES Determine whether unconstrained speech contains signatures capable of identifying the acute effects of psilocybin microdoses. METHODS Natural speech under psilocybin microdoses (0.5 g of psilocybin mushrooms) was acquired from thirty-four healthy adult volunteers (11 females: 32.09 ± 3.53 years; 23 males: 30.87 ± 4.64 years) following a double-blind and placebo-controlled experimental design with two measurement weeks per participant. On Wednesdays and Fridays of each week, participants consumed either the active dose (psilocybin) or the placebo (edible mushrooms). Features of interest were defined based on variables known to be affected by higher doses: verbosity, semantic variability, and sentiment scores. Machine learning models were used to discriminate between conditions. Classifiers were trained and tested using stratified cross-validation to compute the AUC and p-values. RESULTS Except for semantic variability, these metrics presented significant differences between a typical active microdose and the inactive placebo condition. Machine learning classifiers were capable of distinguishing between conditions with high accuracy (AUC [Formula: see text] 0.8). CONCLUSIONS These results constitute first evidence that low doses of serotonergic psychedelics can be identified from unconstrained natural speech, with potential for widely applicable, affordable, and ecologically valid monitoring of microdosing schedules.
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28
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Microdosing with psilocybin mushrooms: a double-blind placebo-controlled study. Transl Psychiatry 2022; 12:307. [PMID: 35918311 PMCID: PMC9346139 DOI: 10.1038/s41398-022-02039-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 06/21/2022] [Accepted: 06/29/2022] [Indexed: 12/12/2022] Open
Abstract
The use of low sub-perceptual doses of psychedelics ("microdosing") has gained popularity in recent years. Although anecdotal reports claim multiple benefits associated with this practice, the lack of placebo-controlled studies severely limits our knowledge of microdosing and its effects. Moreover, research conducted in standard laboratory settings could fail to capture the motivation of individuals engaged or planning to engage in microdosing protocols, thus underestimating the likelihood of positive effects on creativity and cognitive function. We recruited 34 individuals starting to microdose with psilocybin mushrooms (Psilocybe cubensis), one of the materials most frequently used for this purpose. Following a double-blind placebo-controlled experimental design, we investigated the acute and short-term effects of 0.5 g of dried mushrooms on subjective experience, behavior, creativity (divergent and convergent thinking), perception, cognition, and brain activity. The reported acute effects were significantly more intense for the active dose compared to the placebo, but only for participants who correctly identified their experimental condition. These changes were accompanied by reduced EEG power in the theta band, together with preserved levels of Lempel-Ziv broadband signal complexity. For all other measurements there was no effect of microdosing except for few small changes towards cognitive impairment. According to our findings, low doses of psilocybin mushrooms can result in noticeable subjective effects and altered EEG rhythms, but without evidence to support enhanced well-being, creativity and cognitive function. We conclude that expectation underlies at least some of the anecdotal benefits attributed to microdosing with psilocybin mushrooms.
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29
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Murray CH, Tare I, Perry CM, Malina M, Lee R, de Wit H. Low doses of LSD reduce broadband oscillatory power and modulate event-related potentials in healthy adults. Psychopharmacology (Berl) 2022; 239:1735-1747. [PMID: 34613430 PMCID: PMC9847217 DOI: 10.1007/s00213-021-05991-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 09/20/2021] [Indexed: 01/21/2023]
Abstract
RATIONALE Classical psychedelics, including psilocybin and lysergic acid diethylamide (LSD), are under investigation as potential therapeutic agents in psychiatry. Whereas most studies utilize relatively high doses, there are also reports of beneficial effects of "microdosing," or repeated use of very low doses of these drugs. The behavioral and neural effects of these low doses are not fully understood. OBJECTIVES To examine the effects of LSD (13 μg and 26 μg) versus placebo on resting-state electroencephalography (EEG) and event-related potential (ERP) responses in healthy adults. METHODS Twenty-two healthy men and women, 18 to 35 years old, participated in 3 EEG sessions in which they received placebo or LSD (13 μg and 26 μg) under double-blind conditions. During each session, participants completed drug effect and mood questionnaires at hourly intervals, and physiological measures were recorded. During expected peak drug effect, EEG recordings were obtained, including resting-state neural oscillations in scalp electrodes over default mode network (DMN) regions and P300, N170, and P100 ERPs evoked during a visual oddball paradigm. RESULTS LSD dose-dependently reduced oscillatory power across delta, theta, alpha, beta, and gamma frequency bands during both eyes closed and eyes open resting conditions. During the oddball task, LSD dose-dependently reduced ERP amplitudes for P300 and N170 components and increased P100 latency. LSD also produced dose-related increases in positive mood, elation, energy, and anxiety and increased heart rate and blood pressure. On a measure of altered states of consciousness, LSD dose-dependently increased Blissful State, but not other indices of perceptual or sensory effects typical of psychedelic drugs. The subjective effects of the drug were not correlated with the EEG measures. CONCLUSIONS Low doses of LSD produced broadband cortical desynchronization over the DMN during resting state and reduced P300 and N170 amplitudes, patterns similar to those reported with higher doses of psychedelics. Notably, these neurophysiological effects raise the possibility that very low doses of LSD may produce subtle behavioral and perhaps therapeutic effects that do not rely on the full psychedelic experience.
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Affiliation(s)
- Conor H Murray
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave MC3077, Chicago, IL, 60637, USA
| | - Ilaria Tare
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave MC3077, Chicago, IL, 60637, USA
| | - Claire M Perry
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave MC3077, Chicago, IL, 60637, USA
| | - Michael Malina
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave MC3077, Chicago, IL, 60637, USA
| | - Royce Lee
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave MC3077, Chicago, IL, 60637, USA
| | - Harriet de Wit
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave MC3077, Chicago, IL, 60637, USA.
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30
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Correa R, Rodriguez N, Bortolaso M. What is the nature of the alteration of temporality in Trauma-Related Altered States of Consciousness? A neuro-phenomenological analysis✰,✰✰,★,★★. EUROPEAN JOURNAL OF TRAUMA & DISSOCIATION 2022. [DOI: 10.1016/j.ejtd.2021.100227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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31
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Polito V, Liknaitzky P. The emerging science of microdosing: A systematic review of research on low dose psychedelics (1955 - 2021) and recommendations for the field. Neurosci Biobehav Rev 2022; 139:104706. [PMID: 35609684 DOI: 10.1016/j.neubiorev.2022.104706] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 05/09/2022] [Accepted: 05/18/2022] [Indexed: 12/20/2022]
Abstract
The use of low doses of psychedelic substances (microdosing) is attracting increasing interest. This systematic review summarises all empirical microdosing research to date, including a set of infrequently cited studies that took place prior to prohibition. Specifically, we reviewed 44 studies published between 1955 and 2021, and summarised reported effects across six categories: mood and mental health; wellbeing and attitude; cognition and creativity; personality; changes in conscious state; and neurobiology and physiology. Studies showed a wide range in risk of bias, depending on design, age, and other study characteristics. Laboratory studies found changes in pain perception, time perception, conscious state, and neurophysiology. Self-report studies found changes in cognitive processing and mental health. We review data related to expectation and placebo effects, but argue that claims that microdosing effects are largely due to expectancy are premature and possibly wrong. In addition, we attempt to clarify definitional inconsistencies in the microdosing literature by providing suggested dose ranges across different substances. Finally, we provide specific design suggestions to facilitate more rigorous future research.
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Affiliation(s)
- Vince Polito
- School of Psychological Sciences, Macquarie University, Australia.
| | - Paul Liknaitzky
- Turner Institute, School of Psychological Sciences, Monash University, Australia; Department of Psychiatry, School of Clinical Sciences, Monash University, Australia.
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32
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Li H, Zhong Y, Yang S, Wang J, Li X, Xu J, Gao H, Chen G. The potential role of lysergic acid diethylamide for psychological assisted therapy: A meta-analysis of randomised controlled trials in healthy volunteers. Hum Psychopharmacol 2022; 37:e2825. [PMID: 34739739 DOI: 10.1002/hup.2825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 11/10/2022]
Abstract
OBJECTIVE In recent years, interest in using lysergic acid diethylamide (LSD) in psychiatric research and corresponding therapy has increased rapidly. In this meta-analysis, we explored the effects of LSD on healthy subjects with respect to subjective drug effects, blood pressure, heart rate, body temperature and side effects. METHOD PubMed, Embase, and the Cochrane Library were searched from January 2010 to December 2020 for randomized controlled trials (RCTs) on the effects of LSD in healthy people. Subsequently, 5 RCTs with 132 healthy people which focused on the effects of LSD were enrolled in our study. RESULT We found that taking 50, 100 and 200 mcg LSD doses were associated with a significant increase in the maximal difference from the baseline compared to the placebo group among the outcomes of AMRS (Adjective Mood Rating Scale) score. Significant differences existed between the LSD and placebo groups when taking 100 and 200 mcg LSD in acute adverse effects (100 mcg: SMD = .97, 95% confidence interval [CI], .50, 1.44, Z = 4.04, p < .001; 200 mcg: SMD = 1.18, 95% CI, 0.65, 1.72, Z = 4.32, p < .001). CONCLUSIONS Meta-analysis of the subjective effects of LSD in healthy people revealed moderate significant effect sizes in favor of LSD with no significant adverse effects. A 100 mcg dose of LSD has potential for use in psychological-assisted therapy and may improve the mental fitness of patients with disease-related psychiatric distress. Additional clinical trials are necessary to explore the efficacy and safety of LSD as a psychological-assisted therapy.
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Affiliation(s)
- Hang Li
- Department of Clinical Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Yi Zhong
- Department of Clinical Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Siyuan Yang
- Department of Clinical Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Jiahe Wang
- Department of Clinical Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Xiang Li
- Department of Clinical Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Jianguo Xu
- Department of Clinical Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Heng Gao
- Department of Clinical Medicine, The Affiliated Jiangyin Hospital, School of Medicine, Southeast University, Jiangyin, Jiangsu Province, China
| | - Gang Chen
- Department of Clinical Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
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33
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Sekula AD, Downey L, Puspanathan P. Virtual Reality as a Moderator of Psychedelic-Assisted Psychotherapy. Front Psychol 2022; 13:813746. [PMID: 35310225 PMCID: PMC8931418 DOI: 10.3389/fpsyg.2022.813746] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 02/11/2022] [Indexed: 12/20/2022] Open
Abstract
Psychotherapy with the use of psychedelic substances, including psilocybin, lysergic acid diethylamide (LSD), ketamine, and 3,4-methylenedioxymethamphetamine (MDMA), has demonstrated promise in treatment of post-traumatic stress disorder (PTSD), anxiety, addiction, and treatment-resistant depression. Psychedelic-assisted psychotherapy (PP) represents a unique psychopharmacological model that leverages the profound effects of the psychedelic experience. That experience is characterized by strong dependency on two key factors: participant mindset and the therapeutic environment. As such, therapeutic models that utilize psychedelics reflect the need for careful design that promotes an open, flexible, trusting mindset and a supportive setting. To meet this need, the PP model is increasingly supplemented by auxiliary methods, including meditation, relaxation, visualization or spiritual practices. We suggest virtual reality (VR) as a full-spectrum tool able to capitalize on and catalyze the innately therapeutic aspects of the psychedelic experience, such as detachment from familiar reality, alteration of self-experience, augmentation of sensory perception and induction of mystical-type experiences. This is facilitated by VR’s evidenced capacity to: aid relaxation and reduce anxiety; buffer from external stimuli; promote a mindful presence; train the mind to achieve altered states of consciousness (ASC); evoke mystical states; enhance therapeutic alliance and encourage self-efficacy. While these unique VR features appear promising, VR’s potential role in PP remains speculative due to lack of empirical evidence on the combined use of VR and PP. Given the increased commercial interest in this synergy there is an urgent need to evaluate this approach. We suggest specific VR models and their role within PP protocols to inspire future direction in scientific research, and provide a list of potential disadvantages, side effects and limitations that need to be carefully considered. These include sensory overstimulation, cyber-sickness, triggering memories of past traumatic events as well as distracting from the inner experience or strongly influencing its contents. A balanced, evidence-based approach may provide continuity across all phases of treatment, support transition into and out of an ASC, deepen acute ASC experiences including mystical states and enrich the psychotherapeutic process of integration. We conclude that the potential application of VR in modulating psychedelic-assisted psychotherapy demands further exploration and an evidence-based approach to both design and implementation.
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Affiliation(s)
- Agnieszka D. Sekula
- Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, VIC, Australia
- Enosis Therapeutics Pty. Ltd., Melbourne, VIC, Australia
- *Correspondence: Agnieszka D. Sekula,
| | - Luke Downey
- Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, VIC, Australia
- Institute for Breathing and Sleep, Austin Hospital, Melbourne, VIC, Australia
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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: 31] [Impact Index Per Article: 15.5] [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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35
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Holze F, Caluori TV, Vizeli P, Liechti ME. Safety pharmacology of acute LSD administration in healthy subjects. Psychopharmacology (Berl) 2022; 239:1893-1905. [PMID: 34515824 PMCID: PMC9166834 DOI: 10.1007/s00213-021-05978-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/30/2021] [Indexed: 11/04/2022]
Abstract
RATIONALE Lysergic acid diethylamide (LSD) is used in psychiatric and psychological research and investigated as a potential treatment for medical and psychiatric disorders, including depression, anxiety, and cluster headache. OBJECTIVES Safety data on clinical safety are available from small studies but not from larger samples. We report safety pharmacology data from a large pooled study sample on acute effects of LSD in healthy subjects. METHODS We conducted a pooled analysis of four double-blind, randomized, placebo-controlled, crossover studies that included a total of 83 healthy subjects and 131 single-dose administrations of LSD. LSD administrations were matched to dose groups according to measured LSD peak plasma concentrations to adjust for uncertainties in the correct LSD dose in some studies. Single doses were 25, 50, 100, and 200 µg of LSD base. We investigated subjective effects (self-rated any drug effect, good drug effect, bad drug effect, and anxiety), blood pressure, heart rate, body temperature, duration of the acute LSD response, acute (12 h) and subacute (24 h) adverse effects, reports of flashbacks, and liver and kidney function before and after the studies. RESULTS LSD dose-dependently increased subjective, physiologic, and adverse effects. The dose-response curves for the proportions of subjects with a certain amount of a subjective effect were steeper and reached a higher maximum for positive acute subjective effects compared with negative acute subjective effects. Maximal ratings of > 50% good drug effects were reached in 37%, 91%, 96%, and 91% of the LSD administrations at 25, 50, 100, and 200 µg. Maximal ratings of > 50% bad drug effects were reached in 0%, 9%, 27%, 31% at 25, 50, 100, and 200 µg, respectively. Mean ratings of Oceanic Boundlessness were 10%, 25%, 41%, and 44%, and mean ratings of Anxious Ego-Dissolution were 3.4%, 13%, 20%, and 22% at 25, 50, 100, and 200 µg, respectively. The physiologic effects of LSD were moderate. None of the subjects had systolic blood pressure > 180 mmHg at any time. Peak heart rate > 100 beats/min was observed in 0%, 6%, 20%, and 25% of the subjects at 25, 50, 100, and 200 µg, respectively. Maximal heart rates of 129 and 121 beats/min were observed in one subject at the 50 and 200 µg doses, respectively. Peak body temperature > 38° was observed in 0%, 11%, 7%, and 34% at 25, 50, 100, and 200 µg, respectively. Mean acute adverse effect scores on the List of Complaints were 5.6, 9.2, 12, and 13 at 25, 50, 100, and 200 µg, respectively. Kidney and liver function parameters were unaltered. Six subjects reported transient flashback phenomena. CONCLUSIONS The single-dose administration of LSD is safe in regard to acute psychological and physical harm in healthy subjects in a controlled research setting.
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Affiliation(s)
- Friederike Holze
- grid.410567.1Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel and University of Basel, Schanzenstrasse 55, CH-4056 Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Toya V. Caluori
- grid.410567.1Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel and University of Basel, Schanzenstrasse 55, CH-4056 Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Patrick Vizeli
- grid.410567.1Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel and University of Basel, Schanzenstrasse 55, CH-4056 Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Matthias E. Liechti
- grid.410567.1Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel and University of Basel, Schanzenstrasse 55, CH-4056 Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
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Administration of N,N-dimethyltryptamine (DMT) in psychedelic therapeutics and research and the study of endogenous DMT. Psychopharmacology (Berl) 2022; 239:1749-1763. [PMID: 35064294 PMCID: PMC8782705 DOI: 10.1007/s00213-022-06065-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 01/11/2022] [Indexed: 12/20/2022]
Abstract
As with all drugs, the route, form, and/or dose of a substance administered or applied can play a defining role in its overall pharmacology and use as a therapeutic. This review will focus on these factors as they relate to the psychedelic N,N-dimethyltryptamine (DMT). It will examine the positive and negative aspects of different formulations and routes of administration of DMT and the observed effects from such administrations in the form of ayahuasca teas; oral "pharmahuasca"; injections by intravenous (IV) and intramuscular (IM) routes; inhalation, insufflation; and other routes; and high-dose, low-dose, and "micro-dose" effects. The review will consider possible oral route of administration alternatives that would not require concomitant use of a monoamine oxidase inhibitor. The review will then address the current research findings for DMT from in vivo and in vitro studies as well as the possibility that these findings may be revealing the role of endogenous DMT in normal brain function.
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van Elk M, Fejer G, Lempe P, Prochazckova L, Kuchar M, Hajkova K, Marschall J. Effects of psilocybin microdosing on awe and aesthetic experiences: a preregistered field and lab-based study. Psychopharmacology (Berl) 2022; 239:1705-1720. [PMID: 33928421 PMCID: PMC9166866 DOI: 10.1007/s00213-021-05857-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 04/19/2021] [Indexed: 12/14/2022]
Abstract
There is an increased societal trend to engage in microdosing, in which small sub-hallucinogenic amounts of psychedelics are consumed on a regular basis. Following subjective reports that microdosing enhances the experience of nature and art, in the present study we set out to study the effects of psilocybin microdosing on feelings of awe and art perception. In this preregistered combined field- and lab-based study, participants took part in a microdosing workshop after which they volunteered to self-administer a psilocybin microdose or a placebo for three consecutive weeks, while the condition was kept blind to the participants and researchers. Following a 2-week break, the condition assignment was reversed. During each block, participants visited the lab twice to measure the effects of psilocybin microdosing vs. placebo. We used standardized measures of awe, in which participants reported their experiences in response to short videos or when viewing abstract artworks from different painters. Our confirmatory analyses showed that participants felt more awe in response to videos representing funny animals and moving objects in the microdosing compared to the placebo condition. However, about two-third of our participants were breaking blind to their experimental condition. Our exploratory findings suggest that expectancy-effects may be a driving factor underlying the subjective benefits of microdosing.
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Affiliation(s)
- Michiel van Elk
- Institute of Psychology, Leiden University, Wassenaarseweg 52, 2333 AK, Leiden, The Netherlands.
| | - George Fejer
- grid.7177.60000000084992262Department of Psychology, University of Amsterdam, Nieuwe Achtergracht 129B, 1018WT Amsterdam, The Netherlands
| | - Pascal Lempe
- grid.7177.60000000084992262Department of Psychology, University of Amsterdam, Nieuwe Achtergracht 129B, 1018WT Amsterdam, The Netherlands
| | - Luisa Prochazckova
- grid.5132.50000 0001 2312 1970Institute of Psychology, Leiden University, Wassenaarseweg 52, 2333 AK Leiden, The Netherlands
| | - Martin Kuchar
- grid.448072.d0000 0004 0635 6059Forensic Laboratory of Biologically Active Substances, Department of Chemistry of Natural Compounds, University of Chemistry and Technology Prague, Prague, Czech Republic ,grid.447902.cDepartment of Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic
| | - Katerina Hajkova
- grid.448072.d0000 0004 0635 6059Forensic Laboratory of Biologically Active Substances, Department of Chemistry of Natural Compounds, University of Chemistry and Technology Prague, Prague, Czech Republic ,grid.447902.cDepartment of Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic
| | - Josephine Marschall
- grid.5132.50000 0001 2312 1970Institute of Psychology, Leiden University, Wassenaarseweg 52, 2333 AK Leiden, The Netherlands
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van den Berg M, Magaraggia I, Schreiber R, Hillhouse TM, Porter JH. How to account for hallucinations in the interpretation of the antidepressant effects of psychedelics: a translational framework. Psychopharmacology (Berl) 2022; 239:1853-1879. [PMID: 35348806 PMCID: PMC9166823 DOI: 10.1007/s00213-022-06106-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/24/2022] [Indexed: 01/02/2023]
Abstract
RATIONALE Recent trials with psychedelics in major depressive disorder and treatment-resistant depression showed remarkable improvements in depressive symptoms that can last for up to several months after even a single administration. The lack of an appropriate placebo control group-as patients are often able to discriminate the subjective effects of the drug-and an incomplete understanding of the role of the hallucinogenic and mystical experience, hampers the interpretation of these therapeutic effects. OBJECTIVES To control for these factors, we developed a translational framework based on establishing pharmacokinetic/pharmacodynamic (PK/PD) relationships in rodents and humans for hallucinogenic (i.e., discriminative stimulus effects in rodents and humans; head twitch responses in rodents; questionnaires in humans) and therapeutic effects. For the latter, we selected the pattern separation and attentional set-shifting tasks as measures for cognitive flexibility because of their high translational value. We predict that these PK/PD analyses will lead to a more objective evaluation of improvements in patients compared to relying only on the currently used self-reported questionnaires. We hypothesize that-if the role of the hallucinogenic experience is not central in the antidepressant effects of psychedelics-the ED50's for the therapeutic effects will be significantly lower than for the hallucinogenic and mystical effects. CONCLUSION Our framework will help to inform future studies that aim at the elucidation of the mechanism(s) of action of psychedelics in depression, and the role of the acute subjective and/or hallucinogenic experience in their effects.
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Affiliation(s)
- Manon van den Berg
- Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands ,Faculty of Psychology and Neuroscience, Section Neuropsychology & Psychopharmacology, Maastricht University, Maastricht, The Netherlands
| | - Igor Magaraggia
- Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands ,Faculty of Psychology and Neuroscience, Section Neuropsychology & Psychopharmacology, Maastricht University, Maastricht, The Netherlands
| | - Rudy Schreiber
- Faculty of Psychology and Neuroscience, Section Neuropsychology & Psychopharmacology, Maastricht University, Maastricht, The Netherlands.
| | - Todd M. Hillhouse
- Department of Psychology, University of Wisconsin Green Bay, Green Bay, WI USA
| | - Joseph H. Porter
- Department of Psychology, Virginia Commonwealth University, Richmond, USA
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Kelly JR, Gillan CM, Prenderville J, Kelly C, Harkin A, Clarke G, O'Keane V. Psychedelic Therapy's Transdiagnostic Effects: A Research Domain Criteria (RDoC) Perspective. Front Psychiatry 2021; 12:800072. [PMID: 34975593 PMCID: PMC8718877 DOI: 10.3389/fpsyt.2021.800072] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 11/19/2021] [Indexed: 12/12/2022] Open
Abstract
Accumulating clinical evidence shows that psychedelic therapy, by synergistically combining psychopharmacology and psychological support, offers a promising transdiagnostic treatment strategy for a range of disorders with restricted and/or maladaptive habitual patterns of emotion, cognition and behavior, notably, depression (MDD), treatment resistant depression (TRD) and addiction disorders, but perhaps also anxiety disorders, obsessive-compulsive disorder (OCD), Post-Traumatic Stress Disorder (PTSD) and eating disorders. Despite the emergent transdiagnostic evidence, the specific clinical dimensions that psychedelics are efficacious for, and associated underlying neurobiological pathways, remain to be well-characterized. To this end, this review focuses on pre-clinical and clinical evidence of the acute and sustained therapeutic potential of psychedelic therapy in the context of a transdiagnostic dimensional systems framework. Focusing on the Research Domain Criteria (RDoC) as a template, we will describe the multimodal mechanisms underlying the transdiagnostic therapeutic effects of psychedelic therapy, traversing molecular, cellular and network levels. These levels will be mapped to the RDoC constructs of negative and positive valence systems, arousal regulation, social processing, cognitive and sensorimotor systems. In summarizing this literature and framing it transdiagnostically, we hope we can assist the field in moving toward a mechanistic understanding of how psychedelics work for patients and eventually toward a precise-personalized psychedelic therapy paradigm.
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Affiliation(s)
- John R. Kelly
- Department of Psychiatry, Trinity College, Dublin, Ireland
- Department of Psychiatry, Tallaght University Hospital, Dublin, Ireland
| | - Claire M. Gillan
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
- School of Psychology, Trinity College, Dublin, Ireland
- Global Brain Health Institute, Trinity College, Dublin, Ireland
| | - Jack Prenderville
- Transpharmation Ireland Ltd, Institute of Neuroscience, Trinity College, Dublin, Ireland
- Discipline of Physiology, School of Medicine, Trinity College, Dublin, Ireland
| | - Clare Kelly
- Department of Psychiatry, Trinity College, Dublin, Ireland
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
- School of Psychology, Trinity College, Dublin, Ireland
| | - Andrew Harkin
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
- School of Pharmacy and Pharmaceutical Sciences, Trinity College, Dublin, Ireland
| | - Gerard Clarke
- Department of Psychiatry and Neurobehavioral Science, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Veronica O'Keane
- Department of Psychiatry, Trinity College, Dublin, Ireland
- Department of Psychiatry, Tallaght University Hospital, Dublin, Ireland
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
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Abstract
Classic psychedelics, including psilocybin, lysergic acid diethylamide (LSD), dimethyltryptamine, and mescaline, and entactogens/empathogens, especially 3,4-methylenedioxymethamphetamine, have received renewed attention in psychiatric research and may be developed into medications for such indications as anxiety, depression, cluster headache, and posttraumatic stress disorder, among others. However, identifying proper doses is crucial. Controlled study data on dosing using well-characterized pharmaceutical formulations of the substances are scarce. The dose equivalence of different substances, dose-response effects, and subjective effects of different doses are of great interest and practically important for their clinical use in psychotherapy. Furthermore, the so-called microdosing of psychedelics has recently gained popularity, and the first placebo-controlled studies of LSD have been published. This chapter discusses different aspects of psychedelic dosing, including pharmaceutical aspects, definitions and characteristics of different doses, including microdoses, aspects of personalized dosing, and non-pharmacological factors, that can influence the response to psychedelics.
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Psychedelic perceptions: mental health service user attitudes to psilocybin therapy. Ir J Med Sci 2021; 191:1385-1397. [PMID: 34131812 PMCID: PMC8205319 DOI: 10.1007/s11845-021-02668-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 05/26/2021] [Indexed: 12/18/2022]
Abstract
Introduction Despite the rapid advance of psychedelic science and possible translation of psychedelic therapy into the psychiatric clinic, very little is known about mental health service user attitudes. Objectives To explore mental health service user attitudes to psychedelics and psilocybin therapy. Methods A questionnaire capturing demographics, diagnoses, previous psychedelic and other drug use, and attitudes to psychedelics and psilocybin therapy was distributed to mental health service users. Results Ninety-nine participants completed the survey (52% female, mean age 42 years). The majority (72%) supported further research, with 59% supporting psilocybin as a medical treatment. A total of 27% previously used recreational psilocybin, with a male preponderance (p = 0.01). Younger age groups, those with previous psychedelic experience, and those with non-religious beliefs were more likely to have favourable attitudes towards psilocybin. A total of 55% of the total sample would accept as a treatment if doctor recommended, whereas 20% would not. Fewer people with depression/anxiety had used recreational psychedelics (p = 0.03) but were more likely to support government funded studies (p = 0.02). A minority (5%) of people with conditions (psychosis and bipolar disorder) that could be exacerbated by psilocybin thought it would be useful for them. One fifth of the total sample viewed psychedelics as addictive and unsafe even under medical supervision. Concerns included fear of adverse effects, lack of knowledge, insufficient research, illegality, and relapse if medications were discontinued. Conclusions The majority supported further research into psilocybin therapy. Younger people, those with previous recreational psychedelic experience, and those with non-religious beliefs were more likely to have favourable attitudes towards psilocybin therapy. Supplementary information The online version contains supplementary material available at 10.1007/s11845-021-02668-2.
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Dressler HM, Bright SJ, Polito V. Exploring the relationship between microdosing, personality and emotional insight: A prospective study. JOURNAL OF PSYCHEDELIC STUDIES 2021. [DOI: 10.1556/2054.2021.00157] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
AbstractBackround and aimsHaving entered the recent public and research zeitgeist, microdosing involves consuming sub-perceptual doses of psychedelic drugs, allegedly to enhance performance, creativity, and wellbeing. The results of research to date have been mixed. Whereas most studies have reported positive impacts of microdosing, some microdosers have also reported adverse effects. In addition, research to date has revealed inconsistent patterns of change in personality traits. This prospective study explored the relationship between microdosing, personality change, and emotional awareness.MethodsMeasures of personality and alexithymia were collected at two time points. 76 microdosers participated at baseline. Invitations to a follow-up survey were sent out after 31 days, and 24 participants were retained.ResultsConscientiousness increased, while neuroticism decreased across these time points (n = 24). At baseline (N = 76), neuroticism was associated with alexithymia. In addition, neuroticism correlated negatively with duration of prior microdosing experience, and extraversion correlated positively with both duration of prior microdosing experience and lifetime number of microdoses.ConclusionThese results suggest that microdosing might have an impact on otherwise stable personality traits.
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Affiliation(s)
- Hannah M. Dressler
- 1Georg Elias Mueller Institute of Psychology, University of Göttingen, Goßlerstraße 14, 37073 Göttingen, Germany
| | - Stephen J. Bright
- 2School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, 6027, Australia
| | - Vince Polito
- 3Department of Cognitive Science, Macquarie University, NSW, 2109, Australia
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Murphy RJ, Sumner RL, Evans W, Menkes D, Lambrecht I, Ponton R, Sundram F, Hoeh N, Ram S, Reynolds L, Muthukumaraswamy S. MDLSD: study protocol for a randomised, double-masked, placebo-controlled trial of repeated microdoses of LSD in healthy volunteers. Trials 2021; 22:302. [PMID: 33892777 PMCID: PMC8062934 DOI: 10.1186/s13063-021-05243-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 03/31/2021] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Regular ingestion of sub-hallucinogenic doses of psychedelics, referred to as "microdosing", has gained increasing popularity and attention in the press and in online forums, with reported benefits across multiple cognitive and emotional domains. Rigorously controlled studies to date, however, have been limited in scope and have failed to produce results comparable to those reported in the grey literature. METHODS Eighty healthy male participants will receive 14 doses of placebo or 10 μg lysergic acid diethylamide orally every 3rd day over a 6-week treatment protocol. A battery of personality, creativity, mood, cognition, and EEG plasticity measures, as well as resting-state fMRI imaging, will be administered at baseline and at the end of the protocol. Creativity, mood, and plasticity measures will additionally be assessed in the acute phase of the first dose. Daily functioning will be monitored with questionnaires and a wearable sleep and activity tracker. DISCUSSION This study will rigorously examine the claims presented in the microdosing grey literature by pairing a comparable dosing protocol with objective measures. Potential therapeutic implications include future clinical trials to investigate microdosed psychedelics as a standalone treatment or as an augmentation of psychotherapy in the treatment of depression, addiction, eating disorders, obsessive-compulsive disorders, and palliative care. TRIAL REGISTRATION ACTRN12621000436875 . Registered on 19 February 2021.
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Affiliation(s)
- Robin J Murphy
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand.
| | - Rachael L Sumner
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - William Evans
- Mana Health, 7 Ruskin St, Parnell, Auckland, 1052, New Zealand
| | - David Menkes
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, Waikato Clinical Campus, Peter Rothwell Academic Centre, University of Auckland, Pembroke Street, Hamilton, 3240, New Zealand
| | - Ingo Lambrecht
- Regional Cancer & Blood Service, Auckland District Health Board, 2 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Rhys Ponton
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Frederick Sundram
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, University of Auckland, 2 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Nicholas Hoeh
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, University of Auckland, 22-30 Park Avenue, Grafton, Auckland, 1023, New Zealand
| | - Sanya Ram
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Lisa Reynolds
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, University of Auckland, 22-30 Park Avenue, Grafton, Auckland, 1023, New Zealand
| | - Suresh Muthukumaraswamy
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
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Acunzo DJ, Oakley DA, Terhune DB. The neurochemistry of hypnotic suggestion. THE AMERICAN JOURNAL OF CLINICAL HYPNOSIS 2021; 63:355-371. [PMID: 33999774 DOI: 10.1080/00029157.2020.1865869] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A diverse array of studies has been devoted to understanding the neurochemical systems supporting responsiveness to hypnotic suggestions, with implications for experimental and clinical applications of hypnosis. However, this body of research has only rarely been integrated and critically evaluated and the prospects for the reliable pharmacological manipulation of hypnotic suggestibility remain poorly understood. Here we draw on pharmacological, genotyping, neuroimaging, and electrophysiological research to synthesize current knowledge regarding the potential role of multiple widely-studied neurochemicals in response to suggestion. Although we reveal multiple limitations with this body of evidence, we identify converging results implicating different neurochemical systems in response to hypnotic suggestion. We conclude by assessing the extent to which different results align or diverge and outline multiple avenues for future research. Elucidating the neurochemical systems underlying response to suggestion has the potential to significantly advance our understanding of suggestion.
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Ramaekers JG, Hutten N, Mason NL, Dolder P, Theunissen EL, Holze F, Liechti ME, Feilding A, Kuypers KPC. A low dose of lysergic acid diethylamide decreases pain perception in healthy volunteers. J Psychopharmacol 2021; 35:398-405. [PMID: 32842825 PMCID: PMC8054163 DOI: 10.1177/0269881120940937] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Lysergic acid diethylamide (LSD) is an ergot alkaloid derivative with psychedelic properties that has been implicated in the management of persistent pain. Clinical studies in the 1960s and 1970s have demonstrated profound analgesic effects of full doses of LSD in terminally ill patients, but this line of research evaporated after LSD was scheduled worldwide. AIM The present clinical study is the first to revisit the potential of LSD as an analgesic, and at dose levels which are not expected to produce profound mind-altering effects. METHODS Twenty-four healthy volunteers received single doses of 5, 10 and 20 µg LSD as well as placebo on separate occasions. A Cold Pressor Test was administered at 1.5 and 5 h after treatment administration to assess pain tolerance to experimentally evoked pain. Ratings of dissociation and psychiatric symptoms as well as assessments of vital signs were included to monitor mental status as well as safety during treatments. RESULTS LSD 20 µg significantly increased the time that participants were able to tolerate exposure to cold (3°C) water and decreased their subjective levels of experienced pain and unpleasantness. LSD elevated mean blood pressure within the normal range and slightly increased ratings of dissociation, anxiety and somatization. CONCLUSION The present study provides evidence of a protracted analgesic effect of LSD at a dose that is low enough to avoid a psychedelic experience. The present data warrant further research into the analgesic effects of low doses of LSD in patient populations.
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Affiliation(s)
- Johannes G Ramaekers
- Department of Neuropsychology & Psychopharmacology, Faculty of Psychology & Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Nadia Hutten
- Department of Neuropsychology & Psychopharmacology, Faculty of Psychology & Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Natasha L Mason
- Department of Neuropsychology & Psychopharmacology, Faculty of Psychology & Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Patrick Dolder
- Department of Neuropsychology & Psychopharmacology, Faculty of Psychology & Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Eef L Theunissen
- Department of Neuropsychology & Psychopharmacology, Faculty of Psychology & Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Friederike Holze
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Matthias E Liechti
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, University of Basel, Basel, Switzerland
| | | | - Kim PC Kuypers
- Department of Neuropsychology & Psychopharmacology, Faculty of Psychology & Neuroscience, Maastricht University, Maastricht, the Netherlands
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Abstract
This paper introduces a new construct, the 'pivotal mental state', which is defined as a hyper-plastic state aiding rapid and deep learning that can mediate psychological transformation. We believe this new construct bears relevance to a broad range of psychological and psychiatric phenomena. We argue that pivotal mental states serve an important evolutionary function, that is, to aid psychological transformation when actual or perceived environmental pressures demand this. We cite evidence that chronic stress and neurotic traits are primers for a pivotal mental state, whereas acute stress can be a trigger. Inspired by research with serotonin 2A receptor agonist psychedelics, we highlight how activity at this particular receptor can robustly and reliably induce pivotal mental states, but we argue that the capacity for pivotal mental states is an inherent property of the human brain itself. Moreover, we hypothesize that serotonergic psychedelics hijack a system that has evolved to mediate rapid and deep learning when its need is sensed. We cite a breadth of evidences linking stress via a variety of inducers, with an upregulated serotonin 2A receptor system (e.g. upregulated availability of and/or binding to the receptor) and acute stress with 5-HT release, which we argue can activate this primed system to induce a pivotal mental state. The pivotal mental state model is multi-level, linking a specific molecular gateway (increased serotonin 2A receptor signaling) with the inception of a hyper-plastic brain and mind state, enhanced rate of associative learning and the potential mediation of a psychological transformation.
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Affiliation(s)
- Ari Brouwer
- Centre for Psychedelic Research, Imperial College London, London, United Kingdom
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Abstract
A citizen science approach to research has shown that the improvements in mood and cognition associated with psychedelic microdosing are likely due to a placebo effect.
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Affiliation(s)
- Lindsay P Cameron
- Graduate Program in Neuroscience, University of California, Davis, Davis, United States
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Szigeti B, Kartner L, Blemings A, Rosas F, Feilding A, Nutt DJ, Carhart-Harris RL, Erritzoe D. Self-blinding citizen science to explore psychedelic microdosing. eLife 2021; 10:e62878. [PMID: 33648632 PMCID: PMC7925122 DOI: 10.7554/elife.62878] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 01/20/2021] [Indexed: 12/13/2022] Open
Abstract
Microdosing is the practice of regularly using low doses of psychedelic drugs. Anecdotal reports suggest that microdosing enhances well-being and cognition; however, such accounts are potentially biased by the placebo effect. This study used a 'self-blinding' citizen science initiative, where participants were given online instructions on how to incorporate placebo control into their microdosing routine without clinical supervision. The study was completed by 191 participants, making it the largest placebo-controlled trial on psychedelics to-date. All psychological outcomes improved significantly from baseline to after the 4 weeks long dose period for the microdose group; however, the placebo group also improved and no significant between-groups differences were observed. Acute (emotional state, drug intensity, mood, energy, and creativity) and post-acute (anxiety) scales showed small, but significant microdose vs. placebo differences; however, these results can be explained by participants breaking blind. The findings suggest that anecdotal benefits of microdosing can be explained by the placebo effect.
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Affiliation(s)
- Balázs Szigeti
- Centre for Psychedelic Research, Imperial College LondonLondonUnited Kingdom
| | - Laura Kartner
- Centre for Psychedelic Research, Imperial College LondonLondonUnited Kingdom
| | - Allan Blemings
- Centre for Psychedelic Research, Imperial College LondonLondonUnited Kingdom
| | - Fernando Rosas
- Centre for Psychedelic Research, Imperial College LondonLondonUnited Kingdom
- Data Science Institute, Imperial College LondonLondonUnited Kingdom
- Center for Complexity Science, Imperial College LondonLondonUnited Kingdom
| | | | - David J Nutt
- Centre for Psychedelic Research, Imperial College LondonLondonUnited Kingdom
- Centre for Psychiatry, Imperial College LondonLondonUnited Kingdom
| | | | - David Erritzoe
- Centre for Psychedelic Research, Imperial College LondonLondonUnited Kingdom
- Centre for Psychiatry, Imperial College LondonLondonUnited Kingdom
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Bright S, Gringart E, Blatchford E, Bettinson S. A quantitative exploration of the relationships between regular yoga practice, microdosing psychedelics, wellbeing and personality variables. AUSTRALIAN JOURNAL OF PSYCHOLOGY 2021. [DOI: 10.1080/00049530.2021.1882266] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Stephen Bright
- School of Medical and Health Sciences, Edith Cowan University, Perth, Australia
| | - Eyal Gringart
- School of Arts and Humanities, Edith Cowan University, Perth, Australia
| | - Emily Blatchford
- School of Medical and Health Sciences, Edith Cowan University, Perth, Australia
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Abstract
Consciousness has evolved and is a feature of all animals with sufficiently complex nervous systems. It is, therefore, primarily a problem for biology, rather than physics. In this review, I will consider three aspects of consciousness: level of consciousness, whether we are awake or in a coma; the contents of consciousness, what determines how a small amount of sensory information is associated with subjective experience, while the rest is not; and meta-consciousness, the ability to reflect upon our subjective experiences and, importantly, to share them with others. I will discuss and compare current theories of the neural and cognitive mechanisms involved in producing these three aspects of consciousness and conclude that the research in this area is flourishing and has already succeeded to delineate these mechanisms in surprising detail.
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Affiliation(s)
- Chris D Frith
- Wellcome Centre for Human Neuroimaging at University College London, UK
- Institute of Philosophy, Institute of Advanced Study, University of London, UK
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