Classic psychedelics: An integrative review of epidemiology, therapeutics, mystical experience, and brain network function

Language as a Window Into the Altered State of Consciousness Elicited by Psychedelic Drugs

Psychedelics are drugs capable of eliciting profound alterations in the subjective experience of the users, sometimes with long-lasting consequences. Because of this, psychedelic research tends to focus on human subjects, given their capacity to construct detailed narratives about the contents of their consciousness experiences. In spite of its relevance, the interaction between serotonergic psychedelics and language production is comparatively understudied in the recent literature. This review is focused on two aspects of this interaction: how the acute effects of psychedelic drugs impact on speech organization regardless of its semantic content, and how to characterize the subjective effects of psychedelic drugs by analyzing the semantic content of written retrospective reports. We show that the computational characterization of language production is capable of partially predicting the therapeutic outcome of individual experiences, relate the effects elicited by psychedelics with those associated with other altered states of consciousness, draw comparisons between the psychedelic state and the symptomatology of certain psychiatric disorders, and investigate the neurochemical profile and mechanism of action of different psychedelic drugs. We conclude that researchers studying psychedelics can considerably expand the range of their potential scientific conclusions by analyzing brief interviews obtained before, during and after the acute effects. Finally, we list a series of questions and open problems that should be addressed to further consolidate this approach.

Safety, tolerability, pharmacokinetics, and subjective effects of 50, 75, and 100 µg LSD in healthy participants within a novel intervention paradigm: A proof-of-concept study

BACKGROUND

Classic psychedelics hold promise as therapeutics for psychiatric disorders, but require scalable intervention protocols. This proof-of-concept study evaluated the safety, tolerability, pharmacokinetics, and subjective effects of 50, 75, and 100 µg lysergic acid diethylamide (LSD) in healthy adults within a novel intervention paradigm.

METHODS

Up to three participants were administered LSD on the same day in separate rooms, each with a single attendant, after 1 day of preparation. An open-label design and a double-blind placebo-controlled design were used.

RESULTS

Ninety-one percent of participants completed the study. Thirty-two adults (mean age = 28.8 years) received 50 (n = 3), 75 (n = 7), 100 (n = 3) LSD, 50 µg followed by 75 µg LSD (n = 9) 1 week apart, or placebo followed by a 75 µg LSD (n = 10) 1 week apart. There were no serious adverse events. Twenty-eight percent of participants experienced at least one expected mild adverse event, with one expected moderate adverse event. The maximum blood plasma levels occurred between 1.2 and 2 h post-administration, with an apparent half-life between 2.8 and 4.3 h. LSD largely induced greater subjective effects versus placebo.

CONCLUSION

In the current novel intervention paradigm, 50, 75, and 100 µg LSD are tolerable with favourable safety profiles in healthy adults, only mild adverse events during the day of drug administration, and mystical-type subjective experiences. Future studies are needed to evaluate safety, tolerability, subjective effects, and cost-effectiveness in clinical populations.

Perceptions of safety, subjective effects, and beliefs about the clinical utility of lysergic acid diethylamide in healthy participants within a novel intervention paradigm: Qualitative results from a proof-of-concept study

BACKGROUND

Classic psychedelics show promise in the treatment of mental health conditions; however, more scalable intervention protocols are needed to maximize access to these novel therapeutics. In this proof-of-concept study, perceptions of safety, subjective effects, and beliefs about the clinical utility of lysergic acid diethylamide (LSD) were evaluated among healthy participants (N = 31) administered 50 to 100 µg LSD in a treatment paradigm conceptualized as more scalable than traditional approaches to administering classic psychedelics.

METHODS

Semi-structured interviews assessed participants' expectations, experience, and thoughts on the safety and efficacy of the study design. These interviews were transcribed for thematic analysis relating to perceptions of safety, subjective effects, and beliefs about the clinical utility of LSD.

RESULTS

Most participants felt safe throughout the study, with a minority reporting concerns related to having a challenging experience that diminished over time. Participants attributed their feelings of safety to the study structure and support of their attendants, which allowed them to "let go" and immerse themselves in the experience without pre-occupation. Furthermore, participants reported transcendent, mystical-type experiences characteristic of classic psychedelics, with almost half highlighting the prominent role played by music during the acute period of drug action. Finally, participants endorsed support for the clinical utility of LSD in controlled environments, expressing the belief that LSD is safe and has the potential to help others.

CONCLUSION

Findings provide preliminary support for the feasibility of this scalable interventional paradigm and set the stage for future critical research with clinical populations.

Psychedelic use is associated with reduced daily opioid use among people who use illicit drugs in a Canadian setting

BACKGROUND

Research into the therapeutic and naturalistic uses of psychedelics for improving outcomes related to mental health disorders has generated increasing interest in recent years. While controlled clinical trials of psychedelics have signaled benefits for treating substance use disorders, this area has not been well studied in the context of naturalistic psychedelic use. This study sought to investigate the possible relationship between recent naturalistic psychedelic use and subsequent daily illicit opioid use among people who use drugs (PWUD).

METHODS

Data (2006-2018) were drawn from three harmonized prospective cohorts of community-recruited PWUD in Vancouver, Canada. We used multivariable generalized linear mixed-effects modeling (GLMM) to estimate the independent association between psychedelic use and subsequent daily illicit opioid use.

RESULTS

Among 3813 PWUD at baseline, 1093 (29%) reported daily use of illicit opioids and 229 (6%) reported psychedelic use in the past six months. Over study follow-up after adjusting for a range of potential confounders, psychedelic use remained independently associated with a significantly reduced odds of subsequent daily opioid use (Adjusted Odds Ratio: 0.45; 95% Confidence Interval: 0.29 to 0.70).

CONCLUSION

While confirmation in other settings is required, these findings align with growing evidence that psychedelic use may be associated with detectable reductions in subsequent substance use including illicit opioid use.

Why was early therapeutic research on psychedelic drugs abandoned?

BACKGROUND

Advocates of the therapeutic use of psychedelic drugs have argued that a promising approach to treatment was prematurely abandoned in the 1960s primarily because of Richard Nixon's 'War on Drugs'.This paper (1) briefly describes research in the 1950s and 1960s in North America on the use of LSD to treat alcohol dependence, anxiety in terminal illness, and anxiety and depression; and (2) discusses the factors that led to its abandonment.

METHOD

An analysis of historical scholarship on psychedelic research in the 1950s, 1960s and 1970s in North America.

RESULTS

Research on psychedelic drugs in psychiatry was abandoned for a number of reasons that acted in concert. A major factor was that clinical research on psychedelic drugs was caught up in the tighter regulation of pharmaceutical research after the Thalidomide disaster in 1963. Psychedelic drugs also presented special challenges for randomised, placebo-controlled clinical trials in the 1970s that were not as positive as the claims made by their advocates in the 1950s and 1960s. Clinical research became more difficult after 1965 when Sandoz ceased providing psychedelic drugs for research and their nonmedical use was prohibited in 1970.

CONCLUSIONS

The demise of psychedelic drug research was not solely due to the 'War on Drugs'. It was hastened by tighter regulation of pharmaceutical research, the failure of controlled clinical trials to live up to the claims of psychedelic advocates, and the pharmaceutical industry's lack of interest in funding clinical trials.

The association between naturalistic use of psychedelics and co-occurring substance use disorders

OBJECTIVE

Classic psychedelics (LSD, psilocybin, and peyote/mescaline) have been used to support addiction treatment in a variety of contexts ranging from ceremonial use to clinical trials. The aim of this study was to test the hypothesis that past naturalistic use of classic psychedelics would be associated with decreased prevalence of substance use disorder, when controlling for known confounders.

METHODS

This cross-sectional study used 2017 NSDUH survey data to evaluate the association between past use of the classic psychedelics LSD, psilocybin and peyote/mescaline and past year substance dependence or abuse. We calculated adjusted odds ratios by multivariate logistic regression, controlling for a range of sociodemographic variables, use of non-psychedelic illicit drugs and mental health related variables.

RESULTS

A total of 56,276 participants were included in this study. Past use of LSD and psilocybin were associated with increased odds of substance dependence or abuse compared to those who had never used psychedelics before, and this was more likely for those who had used LSD more recently. However, prior use of peyote or mescaline was associated with lower odds of past year substance dependence or abuse compared to people who had never used psychedelics before (aOR = 0.68, p < 0.001). Past use of classic psychedelics was not associated with nicotine dependence.

CONCLUSION

Past use of peyote/mescaline was associated with decreased odds of substance use disorder compared to people who had never used psychedelics before, while past use of LSD or psilocybin was not. It remains unclear whether this difference is due to pharmacological differences between these compounds or simply due to the context in which peyote/mescaline are traditionally taken. Future research should investigate why naturalistic use of different psychedelics is associated with different substance use disorder effects.

Behavioral Psychedelics: Integrating Mind and Behavior to Improve Health and Resilience

One of the most recent and potentially promising advancements in the health sciences has involved the attempted use of psychedelics for treating mental and behavioral health problems, such as anxiety, depression, posttraumatic stress disorder, and addiction. Despite surging scientific and public interest in this work, however, we presently have no standard of care or consensus regarding how best to combine psychotherapy and psychedelics or to assess effectiveness. We discuss these timely issues here through the lens of behavioral psychedelics, which we define as the study of psychedelics to foster intentional changes in habits and behaviors to improve health and resilience. Psychedelics may have the potential to reduce chronic disease risk caused by mental and behavioral rigidity. To fully realize this potential, though, we believe the field must establish best practices and guidelines that include how to induce lasting changes in behavior.

Consciousness alterations in a cohort of young Swiss men: Associations with substance use and personality traits

BACKGROUND

Substance-induced consciousness alterations (CA) have mainly been studied among users of psychedelics but not among people using street drugs.

AIMS

Explore occurrences of three different types of substance-induced CA [ego dissolution (ED), visual pseudo-hallucinations (VPH), anxiety/paranoia (A/P)] and their perceived influences on life, together with their associations with substance use and personality correlates in a general population sample of 25-year-old men.

METHODS

2,796 young Swiss men lifetime substance users completed a self-report questionnaire including history of use (never, former, and current) of different substances categories (psychedelics, cocaine, psychostimulants, ecstasy, MDMA, and other drugs), substance-induced ego dissolution (ED), visual pseudo-hallucinations (VPH) and anxiety/paranoia (A/P), the influence of these CA experiences on life, and personality traits (sensation seeking, sociability, anxiety-neuroticism, and aggression-hostility).

RESULTS

32.2% reported at least one CA (i.e., ED, VPH or A/P), with 20.5% reporting ED, 16.7% VPH, and 14.6% A/P. Former and current use of psychedelics and ketamine was significantly associated with occurrences of all three types of CAs and with a positive influence of CA on life. Associations between the former and current use of other substances and the different types of CA were less consistent, and perceived influences on life were not statistically significant. Sociability was negatively associated with occurrences of all three types of CA. Positive associations were found between anxiety-neuroticism and ED and A/P, between aggression-hostility and A/P, and between sensation seeking and ED and VPH.

CONCLUSION

This study supports the potential for psychedelics to induce CAs perceived as beneficial to life among people using street drugs, possibly reflecting the mechanism underlying the therapeutic potential of psychedelics.

Serotonergic psychedelics for depression: What do we know about neurobiological mechanisms of action?

INTRODUCTION

Current treatment options for major depressive disorder (MDD) have limited efficacy and are associated with adverse effects. Recent studies investigating the antidepressant effect of serotonergic psychedelics-also known as classic psychedelics-have promising preliminary results with large effect sizes. In this context, we conducted a review of the putative neurobiological underpinnings of the mechanism of antidepressant action of these drugs.

METHODS

A narrative review was conducted using PubMed to identify published articles evaluating the antidepressant mechanism of action of serotonergic psychedelics.

RESULTS

Serotonergic psychedelics have serotonin (5HT)2A agonist or partial agonist effects. Their rapid antidepressant effects may be mediated-in part-by their potent 5HT2A agonism, leading to rapid receptor downregulation. In addition, these psychedelics impact brain derived neurotrophic factor and immunomodulatory responses, both of which may play a role in their antidepressant effect. Several neuroimaging and neurophysiology studies evaluating mechanistic change from a network perspective can help us to further understand their mechanism of action. Some, but not all, data suggest that psychedelics may exert their effects, in part, by disrupting the activity of the default mode network, which is involved in both introspection and self-referential thinking and is over-active in MDD.

CONCLUSION

The mechanisms of action underlying the antidepressant effect of serotonergic psychedelics remains an active area of research. Several competing theories are being evaluated and more research is needed to determine which ones are supported by the most robust evidence.

Effects of psilocybin microdosing on awe and aesthetic experiences: a preregistered field and lab-based study

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.

Psychedelics for the treatment of depression, anxiety, and existential distress in patients with a terminal illness: a systematic review

BACKGROUND

Terminally ill patients may experience existential distress, depression, or anxiety, limiting quality of life in the final stage. Existing psychotherapeutic or pharmacological interventions have (time) limited efficacy. Psychedelic treatment may be a safe and effective alternative treatment option.

AIM

Systematically review studies on psychedelic treatment with and without psychotherapy for existential distress, depression, and anxiety in terminally ill patients.

METHODS

Medline, PsycINFO, and Embase were searched for original-data studies on the treatment of depression, anxiety, and existential distress with classical or a-typical psychedelics in patients with a terminal illness, using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

A total of 1850 records were screened, and 33 articles were included in this review: 14 studies on classical psychedelics (DPT, LSD, and psilocybin) and 19 studies on atypical psychedelics (MDMA and ketamine). Results of early pre-post studies are promising but have serious methodological flaws. Recent (controlled) trials with LSD, psilocybin, ketamine, and MDMA are of higher methodological quality and indicate positive effects on existential and spiritual well-being, quality of life, acceptance, and reduction of anxiety and depression with few adverse and no serious adverse effects.

CONCLUSIONS

Both classical and a-typical psychedelics are promising treatment options in patients with terminal illness. To draw final conclusions on effectiveness and safety of psychedelics, we need larger high-quality studies for classical psychedelics and MDMA. Ketamine studies should pay more attention to existential dimensions of well-being and the psychotherapeutic context of the treatment.

Classic Psychedelics in Addiction Treatment: The Case for Psilocybin in Tobacco Smoking Cessation

This manuscript reviews research suggesting that classic psychedelics (5-HT2A receptor agonists) are effective in treating addictions including tobacco use disorder. I review historical research from the 1950s to 1970s suggesting that classic psychedelics are associated with addiction recovery across pharmacologically distinct drugs of addiction. I then review anthropological reports about ceremonial use of classic psychedelics and epidemiological studies that are consistent with anti-addiction efficacy. I review modern research using psilocybin in the treatment of alcohol use disorder and tobacco use disorder. Both lines of research show high success rates in preliminary studies. General anti-addiction efficacy across a variety of classes of addictive drugs is consistent with the notion that the persisting positive behavior change prompted by psychedelic therapy is due to amplification of psychotherapeutic processes. Future research should examine classic psychedelic treatment of additional substance use disorders including for opioids, cocaine, methamphetamine, and cannabis, and other disorders broadly characterized as addictions (e.g., obesity, problem gambling, hypersexual disorder). Future research should also explore addiction treatments with other classic psychedelics including LSD, mescaline, DMT, 5-MeO-DMT, and yet-to-be-discovered compounds. Experimental research is also needed to test different protocols for the delivery of classic psychedelic therapy for addictions. Given the staggering society costs of substance use disorders, including the mortality caused by tobacco smoking, it is critical that public funding be made available for scientists to follow up on promising early findings of classic psychedelics in addiction treatment. The costs and risks of not conducting such research are too great.

Psychedelics and health behaviour change

Healthful behaviours such as maintaining a balanced diet, being physically active and refraining from smoking have major impacts on the risk of developing cancer, diabetes, cardiovascular diseases and other serious conditions. The burden of the so-called 'lifestyle diseases'-in personal suffering, premature mortality and public health costs-is considerable. Consequently, interventions designed to promote healthy behaviours are increasingly being studied, e.g., using psychobiological models of behavioural regulation and change. In this article, we explore the notion that psychedelic substances such as psilocybin could be used to assist in promoting positive lifestyle change conducive to good overall health. Psilocybin has a low toxicity, is non-addictive and has been shown to predict favourable changes in patients with depression, anxiety and other conditions marked by rigid behavioural patterns, including substance (mis)use. While it is still early days for modern psychedelic science, research is advancing fast and results are promising. Here we describe psychedelics' proposed mechanisms of action and research findings pertinent to health behaviour change science, hoping to generate discussion and new research hypotheses linking the two areas. Therapeutic models including psychedelic experiences and common behaviour change methods (e.g., Cognitive Behaviour Therapy, Motivational Interviewing) are already being tested for addiction and eating disorders. We believe this research may soon be extended to help promote improved diet, exercise, nature exposure and also mindfulness or stress reduction practices, all of which can contribute to physical and psychological health and well-being.

How to account for hallucinations in the interpretation of the antidepressant effects of psychedelics: a translational framework

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.

The Potential of Psychedelics for End of Life and Palliative Care

End of life and palliative care has improved in recent decades but the psychopharmacological options available to clinicians and patients in these contexts remain limited. In particular, psychological factors such as depression, existential distress, and well-being remain challenging to address with current medications. Here, we review recent research on the use of psychedelics in clinical settings with a particular focus on patients with life-threatening diagnoses. We propose that psychedelics may provide clinicians with an additional psychopharmacological treatment in the context of end of life and palliative care.

Beating Pain with Psychedelics: Matter over Mind?

Basic pain research has shed light on key cellular and molecular mechanisms underlying nociceptive and phenomenological aspects of pain. Despite these advances, [[we still yearn for] the discovery of novel therapeutic strategies to address the unmet needs of about 70% of chronic neuropathic pain patients whose pain fails to respond to opioids as well as to other conventional analgesic agents. Importantly, a substantial body of clinical observations over the past decade cumulatively suggests that the psychedelic class of drugs may possess heuristic value for understanding and treating chronic pain conditions. The present review presents a theoretical framework for hitherto insufficiently understood neuroscience-based mechanisms of psychedelics' potential analgesic effects. To that end, searches of PubMed-indexed journals were performed using the following Medical Subject Headings' terms: pain, analgesia, inflammatory, brain connectivity, ketamine, psilocybin, functional imaging, and dendrites. Recursive sets of scientific and clinical evidence extracted from this literature review were summarized within the following key areas: (1) studies employing psychedelics for alleviation of physical and emotional pain; (2) potential neuro-restorative effects of psychedelics to remediate the impaired connectivity underlying the dissociation between pain-related conscious states/cognitions and the subcortical activity/function leading to the eventual chronicity through immediate and long-term effects on dentritic plasticity; (3) anti-neuroinflammatory and pro-immunomodulatory actions of psychedelics as the may pertain to the role of these factors in the pathogenesis of neuropathic pain; (4) safety, legal, and ethical consideration inherent in psychedelics' pharmacotherapy. In addition to direct beneficial effects in terms of reduction of pain and suffering, psychedelics' inclusion in the analgesic armamentarium will contribute to deeper and more sophisticated insights not only into pain syndromes but also into frequently comorbid psychiatric condition associated with emotional pain, e.g., depressive and anxiety disorders. Further inquiry is clearly warranted into the above areas that have potential to evolve into further elucidate the mechanisms of chronic pain and affective disorders, and lead to the development of innovative, safe, and more efficacious neurobiologically-based therapeutic approaches.

Psilocybin, a Naturally Occurring Indoleamine Compound, Could Be Useful to Prevent Suicidal Behaviors

The available interventions for people who are at risk of suicide have limited efficacy. Recently, research on new mental health treatments has started to consider psychedelic compounds, particularly psilocybin, a molecule with a few thousand years of history of use in human societies. The possible effects of psilocybin on suicidal ideation and behaviors have not been specifically studied yet; however, the current knowledge on the suicidal process and the available data on es/ketamine suggest that psylocibin could be used to modulate the thoughts and behavioral patterns in individuals who are at risk of suicidal behaviors. Here, we summarize the available evidence on the possible mechanisms underlying psilocybin positive effects on suicide risk. Major pathways related to suicidal behaviors that might be modulated by psylocibin include serotonin receptors. Specifically, psylocibin directly stimulates the serotonin 2A receptor (5HT_2A), targeting the inflammatory and oxidative stress pathways and leading to a rapid increase in brain plasticity and inflammation suppression and increases in cognitive flexibility, spirituality, and empathy. We also present preliminary epidemiological data and provide a rationale for studying psilocybin in individuals with suicidal ideation or who are at risk of suicidal behaviors. This review presents a framework to understand the basis for psilocybin use in individuals who are at risk of suicidal behaviors and calls for clinical studies.

Novel Treatment Approaches for Substance Use Disorders: Therapeutic Use of Psychedelics and the Role of Psychotherapy

Purpose of Review

The use of psychedelics in a therapeutical setting has been reported for the treatment of various diagnoses in recent years. However, as psychedelic substances are still commonly known for their (illicit) recreational use, it may seem counterintuitive to use psychedelic therapy to treat substance use disorders. This review aims to discuss how psychedelics can promote and intensify psychotherapeutic key processes, in different approaches like psychodynamic and cognitive behavioral therapy, with a spotlight on the treatment of substance use disorders (SUD).

Recent Findings

There is promising evidence of feasibility, safety, and efficacy of psychedelic therapy in SUD. In the whole process of former and current psychedelic therapy regimes that have shown to be safe and efficacious, various psychotherapeutic elements, both psychodynamic and behavioral as well as other approaches, can be identified, while a substantial part of the assumed mechanism of action, the individual psychedelic experience, cannot be distinctly classified to just one approach.

Summary

Psychedelic therapy consists of a complex interaction of pharmacological and psychological processes. When administered in well-defined conditions, psychedelics can serve as augmentation of different psychotherapy interventions in the treatment of SUD and other mental disorders, regardless of their theoretical origin.

Driving while under the influence of hallucinogens: Prevalence, correlates, and risk profiles

BACKGROUND

Hallucinogen use is rising in the US, yet little is known regarding the prevalence and psychosocial/behavioral correlates of driving under the influence of these drugs.

METHODS

This study examined data from 4447 individuals ages 16-64 who reported past-year hallucinogen use in the 2016-2018 National Survey on Drug Use and Health. Prevalence estimates (with 95% confidence intervals [CIs]) were calculated for driving under the influence of hallucinogens (DUIH). Logistic regression examined psychosocial/behavioral correlates of DUIH, and latent class analysis (LCA) characterized subgroups of individuals reporting DUIH.

RESULTS

The prevalence of past-year hallucinogen use was 2.42% (CI = 2.30-2.54) and, in the general population, the prevalence of DUIH was 0.21%. Among past-year hallucinogen users, 8.94% (CI = 7.74-10.31) reported DUIH on at least one occasion over the previous 12 months. The probability of DUIH increased significantly with more frequent use. Compared to individuals who used hallucinogens and did not report DUIH, individuals reporting DUIH were significantly more likely to report mental health problems; use of other illicit drugs; selling drugs; a past-year arrest; or driving under the influence of alcohol, cannabis, or other illicit drugs. LCA identified three classes of individuals reporting DUIH, characterized by: use of and driving under the influence of cannabis; use of and driving under the influence of cannabis and other illicit drugs; and mental health concerns.

CONCLUSIONS

Nearly one in ten individuals who report using hallucinogens also report driving under the influence of hallucinogens-drugs that affect perception and risk-taking, with alarming implications for driving safety.

Serotonergic Psychedelics in Neural Plasticity

Psychedelics, compounds that can induce dramatic changes in conscious experience, have been used by humans for centuries. Recent studies have shown that certain psychedelics can induce neural plasticity by promoting neurite growth and synapse formation. In this review, we focus on the role of classical serotonergic psychedelics in neural plasticity and discuss its implication for their therapeutic potentials.

5-HT2 Receptor Subfamily and the Halogen Bond Promise

The binding of C-4-halogenated 1-(4-X-2,5-dimethoxyphenyl)-2-aminopropane (DOX) serotonin agonist psychedelics at all three 5-HT₂ receptor subtypes is up to two orders of magnitude stronger for X = Cl, Br, or I (but not F) than when C-4 bears a hydrogen atom and more than expected from their hydrophobicities. Our docking and molecular dynamics simulations agree with the fact that increasing the polarizability of halogens results in halogen-oxygen distances to specific backbone C═O groups, and C-X···O angles, in ranges expected for halogen bonds (XBs), which could contribute to the high affinities observed. Good linear correlations are found for each receptor type, indicating that the binding pocket-ligand affinity is enhanced as the XB interaction becomes stronger (i.e., I ≈ Br > Cl > F). It is also striking to note how the linear equations unveil that the receptor's response on the strength of the XB interaction is quite similar among 5-HT_2A and 5-HT_2C, whereas the 5-HT_2B's sensitivity is less. The calculated dipole polarizabilities in the binding pocket of the receptors reflect the experimental affinity values, indicating that less-polarizable and harder binding sites are more prone to XB formation.

Lifetime use of psychedelics is associated with better mental health indicators during the COVID-19 pandemic

Background and aims

The COVID-19 pandemic and its consequences represent a major challenge to the mental health and well-being of the general population. Building on previous work on the potential long-term benefits of psychedelics, we hypothesized that lifetime use of these drugs could be linked to better mental health indicators in the context of the ongoing pandemic.

Methods

Two anonymous online surveys were conducted between April and June 2020, including questions about lifetime experience with psychedelics and other psychoactive drugs, and psychometric scales designed to measure personality traits, anxiety, negative, and positive affect, well-being, and resilience. Principal component analysis was applied to divide the sample into groups of subjects based on their drug use reports.

Results

Five thousand six hundred eighteen participants (29.15 0.12 years, 71.97% female) completed both surveys and met the inclusion criteria, with 32.43% of the sample reporting at least one use of a psychedelic drug. Preliminary analyses showed that certain psychedelics were linked to improved mental health indicators, while other psychoactive drugs exhibited the opposite behavior. Lifetime psychedelic use was linked to increased openness and decreased conscientiousness, and to higher scores of positive affect. The reported number of past psychedelic experiences predicted higher scores of the secondary personality trait beta factor, which has been interpreted as a measure of plasticity. No significant associations between lifetime use of psychedelics and indicators of impaired mental health were observed.

Conclusion

We did not find evidence of an association between lifetime use of psychedelics and poor mental health indicators. Conversely, experience with psychedelic drugs was linked to increased positive affect and to personality traits that favor resilience and stability in the light of the ongoing crisis.

Deep Network Pharmacology: Targeting Glutamate Systems as Integrative Treatments for Jump-Starting Neural Networks and Recovery Trajectories

Significant advances in pharmacological treatments for mental illness and addiction will require abandoning old monoaminergic theories of psychiatric disorders and traditionally narrow approaches to how we conduct treatment research. Reframing our efforts with a view on integrative treatments that target core neural network function and plasticity may provide new approaches for lifting patients out of chronic psychiatric symptom sets and addiction. For example, we discuss new treatments that target brain glutamate systems at key transition points within longitudinal courses of care that integrate several treatment modalities. A reconsideration of what our novel and already available medications are intended to achieve and how and when we deliver them for patients with complex illness trajectories could be the key to unlocking new advances in general and addiction psychiatry.

New Insights Into the Clinical and Nonclinical Effects of Psychedelic Substances

Abstract. After decades of stagnation, research on psychedelic substances (such as lysergic acid diethylamide [LSD], psilocybin, or N,N-dimethyltryptamine [DMT]) has experienced a renaissance over the last 10 years, with various major research programs being conducted across Europe and the United States. This research primarily investigates the potential of psychedelics in the treatment of mental health disorders, their short- and long-term effects on recreational users, and the neurological and cognitive processes responsible for their effects. The present review provides a concise summary of the most recent insights gained from this research. We briefly outline the history of psychedelic research, the objective and subjective effects caused by these substances, the prevalence and socio-psychological correlates of their use, as well as their potential for harm. Subsequently, we review empirical research on the beneficial effects of psychedelics in clinical samples, focusing on their efficacy in the treatment of major depression, anxiety, and substance use disorders, and discuss research on the proposed neural and cognitive mechanisms behind these effects. We then review research on their effects on healthy subjects, focusing on psychological well-being as well as changes in personality, nature-relatedness, and creativity. Finally, we review empirical evidence regarding the long-term effects of single experiences with psychedelics and conclude with a summary and outlook.

Spontaneous Spiritual Awakenings: Phenomenology, Altered States, Individual Differences, and Well-Being

Spontaneous Spiritual Awakenings (SSAs) are subjective experiences characterised by a sudden sense of direct contact, union, or complete nondual merging (experience of oneness) with a perceived ultimate reality, the universe, "God," or the divine. These profound transformative experiences have scarcely been researched, despite extensive anecdotal evidence suggesting their potential to catalyse drastic, long-term, and often positive shifts in perception, world-view, and well-being. The aims of this study were to investigate the phenomenological variances of these experiences, including the potential differences between SSAs and Spontaneous Kundalini Awakenings (SKAs), a subset of awakening experiences that the authors postulate may produce a higher likelihood of both physical and negative effects; to explore how these experiences compare to other altered states of consciousness (ASCs), including those mediated by certain psychedelic substances; and understand their impact on well-being. Personality trait absorption and temporal lobe lability (TLL) were assessed as predictors of Spontaneous Spiritual and Kundalini Awakenings (SSA/SKAs). A mixed within and between-participants self-report survey design was adopted. A total of 152 participants reporting their most powerful SSA/SKAs completed questionnaires measuring nondual, kundalini, and mystical experience, as well as depth of ASC, and trait absorption and TLL. Spontaneous Kundalini Awakenings were found to be significantly more physical, but not significantly more negative than SSAs, and overall, both sets of experiences were perceived to be overwhelmingly more positive than negative, even in cases where the experience was initially challenging. The phenomenological distribution of SSA/SKAs was similar to other measured ASCs although greater in magnitude, and appeared most similar in distribution and in magnitude to drug-induced ASCs, particularly classic psychedelics DMT and psilocybin. Temporal lobe lability and trait absorption were found to predict the SSA/SKA experience. The limitations and implications of these findings are discussed.

Psychedelics and Psychedelic-Assisted Psychotherapy

(Reprinted with permission from The American Journal of Psychiatry 2020; 177:391-410).

Psychedelic-assisted therapy for functional neurological disorders: A theoretical framework and review of prior reports

Functional neurological disorders (FNDs), which are sometimes also referred to as psychogenic neurological disorders or conversion disorder, are common disabling neuropsychiatric disorders with limited treatment options. FNDs can present with sensory and/or motor symptoms, and, though they may mimic other neurological conditions, they are thought to occur via mechanisms other than those related to identifiable structural neuropathology and, in many cases, appear to be triggered and sustained by recognizable psychological factors. There is intriguing preliminary evidence to support the use of psychedelic‐assisted therapy in a growing number of psychiatric illnesses, including FNDs. We review the theoretical arguments for and against exploring psychedelic‐assisted therapy as a treatment for FNDs. We also provide an in‐depth discussion of prior published cases detailing the use of psychedelics for psychosomatic conditions, analyzing therapeutic outcomes from a contemporary neuroscientific vantage as informed by several recent neuroimaging studies on psychedelics and FNDs.

The Alkaloids from Lophophora diffusa and Other "False Peyotes"

Commonly, false peyote refers to Lophophora diffusa. However, several other unrelated cacti go by this colloquial name. They either resemble "true" peyote, Lophophora williamsii, or are found in similar habitats. To date, over 40 different alkaloids have been isolated from the Lophophora genus. Of these, only the pharmacological actions of mescaline (1) have been extensively investigated. The major alkaloid in L. diffusa is pellotine (2), a tetrahydroisoquinoline (THIQ), which was briefly marketed as a sleeping aid around the beginning of the 20th century, following reports of its hypnotic properties in humans. Pharmacological experiments with the Lophophora THIQs were performed at the turn of the 20th century, whereas the chemical synthesis was not realized until several decades later. The biosynthetic pathways of the main Lophophora alkaloids were reported at the end of the 1960s. In this review, the relationship of the different "false peyotes" to L. williamsii, in regard to their alkaloid content, the bio- and chemical synthesis of the most relevant alkaloids, and their corresponding pharmacology will be outlined and discussed.

Psychedelics and Consciousness: Distinctions, Demarcations, and Opportunities

Psychedelic substances produce unusual and compelling changes in conscious experience that have prompted some to propose that psychedelics may provide unique insights explaining the nature of consciousness. At present, psychedelics, like other current scientific tools and methods, seem unlikely to provide information relevant to the so-called "hard problem of consciousness," which involves explaining how first-person experience can emerge. However, psychedelics bear on multiple "easy problems of consciousness," which involve relations between subjectivity, brain function, and behavior. In this review, we discuss common meanings of the term "consciousness" when used with regard to psychedelics and consider some models of the effects of psychedelics on the brain that have also been associated with explanatory claims about consciousness. We conclude by calling for epistemic humility regarding the potential for psychedelic research to aid in explaining the hard problem of consciousness while pointing to ways in which psychedelics may advance the study of many specific aspects of consciousness.

Working with Weirdness: A Response to "Moving Past Mysticism in Psychedelic Science"

In response to a recent call to rid psychedelic science of the concept of mystical experience, we argue that acknowledging the varieties and weirdness of psychedelic experiences should be at the heart of any research program on this topic. We highlight the rich tradition and scientific tools for studying mystical-type experiences, their relevance for understanding the therapeutic effects of psychedelics, as well as the need for more diversity in the experiences and participants included in this research.

Use of hallucinogens in Slovakia: Does it differ from global trends?

BACKGROUND

People have been using hallucinogens for thousands of years and interest in these substances has grown in recent years. The aim of this study was to determine the basic socio-demographic data, preferences, experiences, and attitudes associated with hallucinogen use in Slovakia.

METHODS

A cross-sectional research design was used whereby an online survey included participants who had had at least one experience with hallucinogens (N = 422, age M = 27.78; SD = 7.84; SE = 0.38; 35.1% females). Due to the illegal, intimate, and minority nature of the phenomena studied, data was collected using the snowball sampling method via an online social network in groups that declared a drug focus.

RESULTS

Users of hallucinogens were mostly employed (61,8%) and in some form of partnership (57,6%); they usually have a high school diploma (46,68%) or a university degree (45,41%). They most often use psilocybin mushrooms, while the age of initial use (M = 19,61; SD = 5,39) as well as lifetime frequency use (M = 18,26; SD =  24,21; Median =  10) are similar to global trends. Free use without rituals was preferred to ceremonial use. In general, our sample of hallucinogen users considered the integration of psychedelic experiences to be simple rather than challenging. Concurrently, they tended to see hallucinogens as useful to humans, but realised that they are not without risk and can be somewhat dangerous. Males used hallucinogens for the first time at a younger age (p < .05, r = -.12), used more hallucinogens during their lifetime (p <.001, r = -.23), and demanded decriminalisation and legalisation more (p <.01, r = -.13) than females.

CONCLUSION

Slovak users of hallucinogens in our sample showed similar usage trends as users abroad. Even though both males and females perceive and evaluate hallucinogens very similarly, females are significantly more careful in using these substances.

A qualitative and quantitative account of patient's experiences of ketamine and its antidepressant properties

BACKGROUND

Ketamine is central to one of the most rapidly growing areas of neuroscientific research into novel treatments for depression. Limited research has indicated that the psychedelic properties of ketamine may play a role in its antidepressant effects.

AIM

The aim of the current study was to explore the psychedelic experiences and sustained impact of ketamine in major depressive disorder.

METHODS

In the current study, ketamine (0.44 mg/kg) was administered to 32 volunteers with major depressive disorder in a crossover design with the active-placebo remifentanil, in a magnetic resonance imaging (MRI) environment. The 11-dimension altered states of consciousness questionnaire and individual qualitative interviews were used to capture the acute psychedelic experience. The Montgomery-Asberg Depression Rating Scale and further interviewing explored lasting effects. The second qualitative interview took place ⩾3 weeks post-ketamine.

RESULTS

Greater antidepressant response (reduction in Montgomery-Asberg Depression Rating Scale at 24 h) correlated with the 11-dimension altered states of consciousness dimensions: spirituality, experience of unity, and insight. The first qualitative interview revealed that all participants experienced perceptual changes. Additional themes emerged including loss of control and emotional and mood changes. The final interview showed evidence of a psychedelic afterglow, and changes to perspective on life, people, and problems, as well as changes to how participants felt about their depression and treatments.

CONCLUSIONS

The current study provides preliminary evidence for a role of the psychedelic experience and afterglow in ketamine's antidepressant properties. Reflexive thematic analysis provided a wealth of information on participants' experience of the study and demonstrated the psychedelic properties of ketamine are not fully captured by commonly used questionnaires.

The Potential Role of Serotonergic Hallucinogens in Depression Treatment

Due to an increasing number of depression diagnoses and limited effective treatments, researchers continue to explore novel therapeutic strategies for this disorder. Recently, interest has revolved around the use of serotonergic psychedelics to reduce the symptoms of depression. In this systematic review, we summarize the currently available knowledge on the safety and efficacy of psychedelic substances for the treatment of depression. A literature search of the PubMed/MEDLINE database identified 14 clinical trials from the last 10 years that examined the use of psilocybin, MDMA, DMT, or LSD for the treatment of depression symptoms. Some psychedelics, especially psilocybin, demonstrated an ability to reduce depressive symptoms as measured by several psychological scales, which was often sustained for months after the last psychedelic session. Moreover, one study revealed that psilocybin has comparable efficacy to escitalopram in the treatment of depression. None of the studies reported any serious adverse events associated with psychedelic administration. The reviewed studies suggest that psychedelics have great potential in depression therapy and, after addressing and overcoming the current study limitations, may be used as a novel method of treating depression in the future.

Classic psychedelics in the treatment of substance use disorder: Potential synergies with twelve-step programs

Several pilot studies have provided evidence supporting the potential of classic psychedelics like psilocybin in the treatment of substance use disorders (SUDs). If larger trials confirm efficacy, classic psychedelic-assisted psychotherapy may eventually be integrated into existing addiction treatments such as cognitive behavioral therapy, contingency management, and medication-assisted therapies. Many individuals seeking treatment for SUDs also join twelve-step facilitation (TSF) programs like Alcoholics Anonymous (AA), which are among the most widely available and accessed treatments for alcohol use disorder worldwide. For such individuals, engaging in classic psychedelic-assisted psychotherapy could be seen as controversial, as members of AA/TSF programs have historically rejected medication-assisted treatments in favor of a pharmacotherapy-free approach. We argue that classic psychedelics and the subjective experiences they elicit may represent a special, more compatible case than conventional medications. In support of this claim, we describe Bill Wilson's (the founder of AA) little known experiences with psychedelics and on this basis, we argue that aspects of classic psychedelic treatments could complement AA/TSF programs. We provide a review of clinical trials evaluating psychedelics in the context of SUDs and discuss their potential large-scale impact should they be ultimately integrated into AA/TSF.

Exploring the Use of Psilocybin Therapy for Existential Distress: A Qualitative Study of Palliative Care Provider Perceptions

There is a growing body of research suggesting that palliative care patients coping with existential distress may benefit from psilocybin. However, there is a large gap regarding the perceptions of palliative care providers who may provide education, counseling services, recommendations, and/or prescriptions for psilocybin if it is decriminalized, commercialized, and/or federally rescheduled and legalized. The aim of this study was to explore the experiences and perceptions of interdisciplinary palliative care providers regarding existential distress and the use of psilocybin therapy. Five (n = 5) health care providers from a hospital-based palliative care team completed a semi-structured interview related to their experiences supporting patients with existential distress and their beliefs and attitudes related to psilocybin as a possible treatment modality. A qualitative descriptive approach was used to identify key themes which included: 1) multiple barriers to addressing existential distress at the cultural, institutional/organizational, relational, and individual levels, 2) the duality and power of presence, 3) suffering as an intrinsically subjective phenomenon, and 4) uncertainty about the risks and benefits of psilocybin. To inform an inclusive, safe, and holistic approach, more research is needed regarding the possible integration of psilocybin therapy within palliative care for the treatment of existential distress.

Cannabis-induced oceanic boundlessness

BACKGROUND

Despite tetrahydrocannabinol (THC)'s reputation for creating dramatic effects at high doses, empirical work rarely addresses cannabis's impact on subjective responses common to the tryptamine psychedelics. We focused on these effects because they have preceded and covaried with the therapeutic impact of psilocybin in previous work.

AIMS

The current study examined if self-reported responses to cannabis products might parallel those found in clinical trials of psilocybin administration. We also investigated if measures of demographics and cannabis use might correlate with these responses.

METHODS

Participants reported the subjective effect of their highest THC experience using 27 items that assess oceanic boundlessness, a correlate of mystical experiences. They also answered infrequency items and questions on demographics and cannabis consumption.

RESULTS

In an effort to address concerns about replication, we divided respondents who passed infrequency items into two random samples. Self-reported "breakthrough" experiences were significantly greater than zero but significantly lower than those reported in randomized clinical trials of psilocybin (17-19% vs. 59%). Total scores covaried with perceived dosages of THC, but only in one sample. Heavier users of cannabis reported lower scores.

CONCLUSIONS

Self-report data suggest that high doses of cannabis can create subjective effects comparable to those identified in trials of psilocybin that precede relief from cancer-related distress, treatment-resistant depression, alcohol problems, and cigarette dependence. Given the disparate mechanisms of action, comparing THC-induced to psilocybin-induced effects might improve our understanding of the mechanisms underlying subjective experiences. This work might also support the development of a cannabis-assisted psychotherapy comparable to psilocybin-assisted psychotherapy.

The Setting Questionnaire for the Ayahuasca Experience: Questionnaire Development and Internal Structure

The growing interest in research on psychedelic consumption in naturalistic contexts and their possible medical and therapeutic benefits requires assessment of the relationships between the substance and the individual who consumes it (set) and its context of use (setting). This study provides a novel measurement scale for the setting of Ayahuasca consumption, the Setting Questionnaire for the Ayahuasca Experience (SQAE), and examines its psychometric properties. Construction of the scale began with a literature review, followed by interviews on 19 Ayahuasca users from different backgrounds and different consumption experience, and an online survey for quantitative data collection (n = 2,994). Exploratory Graph Analysis (EGA) was used to investigate the questionnaire's dimensional structure with (n = 1,497, half of the sample), and multidimensional item response theory (MIRT) was used to compare the fit of the theoretical dimensions with the EGA proposed dimensions (n = 1,497, independent other half). EGA identified six dimensions, which corresponded partially to the theorized model (Leadership, Decoration, Infrastructure, Comfort, Instruction, and Social). The MIRT comparison found that the proposed theoretical model fit significantly better than the EGA model, providing support for the former (χ2/df = 1,967; CFI = 0,972; TLI = 0,969; RMSEA = 0,059; WRMR = 1,087). Our findings present evidence of validity of this instrument, justifying its use for future research on the influence of the setting during the ayahuasca experience. Its findings may provide a basis for expanding the settings investigated in the use of psychedelics in general.

Predicting changes in substance use following psychedelic experiences: natural language processing of psychedelic session narratives

Background: Experiences with psychedelic drugs, such as psilocybin or lysergic acid diethylamide (LSD), are sometimes followed by changes in patterns of tobacco, opioid, and alcohol consumption. But, the specific characteristics of psychedelic experiences that lead to changes in drug consumption are unknown.Objective: Determine whether quantitative descriptions of psychedelic experiences derived using Natural Language Processing (NLP) would allow us to predict who would quit or reduce using drugs following a psychedelic experience.Methods: We recruited 1141 individuals (247 female, 894 male) from online social media platforms who reported quitting or reducing using alcohol, cannabis, opioids, or stimulants following a psychedelic experience to provide a verbal narrative of the psychedelic experience they attributed as leading to their reduction in drug use. We used NLP to derive topic models that quantitatively described each participant's psychedelic experience narrative. We then used the vector descriptions of each participant's psychedelic experience narrative as input into three different supervised machine learning algorithms to predict long-term drug reduction outcomes.Results: We found that the topic models derived through NLP led to quantitative descriptions of participant narratives that differed across participants when grouped by the drug class quit as well as the long-term quit/reduction outcomes. Additionally, all three machine learning algorithms led to similar prediction accuracy (~65%, CI = ±0.21%) for long-term quit/reduction outcomes.Conclusions: Using machine learning to analyze written reports of psychedelic experiences may allow for accurate prediction of quit outcomes and what drug is quit or reduced within psychedelic therapy.

Protocol for Outcome Evaluation of Ayahuasca-Assisted Addiction Treatment: The Case of Takiwasi Center

The present study describes the protocol for the Ayahuasca Treatment Outcome Project (ATOP) with a special focus on the evaluation of addiction treatment services provided through Takiwasi Center, the first ATOP study site. The goal of the project is to assess treatment outcomes and understand the therapeutic mechanisms of an Ayahuasca-assisted, integrative treatment model for addiction rehabilitation in the Peruvian Amazon. The proposed intervention protocol highlights the significance of treatment setting in the design, delivery, and efficacy of an addiction rehabilitation program that involves the potent psychedelic tea known as Ayahuasca. After describing the context of the study, we put forth details about our mixed-methods approach to data collection and analysis, with which we seek to gain an understanding of why, how, and for whom this specific ayahuasca-assisted treatment program is effective across a range of outcomes. The ATOP protocol employs qualitative research methods as a means to determine which aspects of the setting are meaningful to clients and practitioners, and how this may correlate with outcome measures. This paper delineates the core principles, methods, and measures of the overall ATOP umbrella, then discusses the role of ATOP in the context of the literature on long-term residential programs. To conclude, we discuss the strengths and limitations of the protocol and the intended future of the project.

Losing Meaning: Philosophical Reflections on Neural Interventions and their Influence on Narrative Identity

The profound changes in personality, mood, and other features of the self that neural interventions can induce can be disconcerting to patients, their families, and caregivers. In the neuroethical debate, these concerns are often addressed in the context of possible threats to the narrative self. In this paper, I argue that it is necessary to consider a dimension of impacts on the narrative self which has so far been neglected: neural interventions can lead to a loss of meaning of actions, feelings, beliefs, and other intentional elements of our self-narratives. To uphold the coherence of the self-narrative, the changes induced by neural interventions need to be accounted for through explanations in intentional or biochemical terms. However, only an explanation including intentional states delivers the content to directly ascribe personal meaning, i.e., subjective value to events. Neural interventions can deprive events of meaning because they may favor a predominantly biochemical account. A loss of meaning is not inherently negative but it can be problematic, particularly if events are affected one was not prepared or willing to have stripped of meaning. The paper further examines what it is about neural interventions that impacts meaning by analyzing different methods. To which degree the pull towards a biochemical view occurs depends on the characteristics of the neural intervention. By comparing Deep Brain Stimulation, Prozac, Ritalin, psychedelics, and psychotherapy, the paper identifies some main factors: the rate of change, the transparency of the causal chain, the involvement of the patient, and the presence of an acute phenomenological experience.

The Subjective Effects of Psychedelics Are Necessary for Their Enduring Therapeutic Effects

Classic psychedelics produce altered states of consciousness that individuals often interpret as meaningful experiences. Across a number of human studies, when the participant-rated intensity of the overall drug effects are statistically controlled for, certain subjective effects predict therapeutic and other desirable outcomes. Underlying neurobiological mechanisms are likely necessary but not sufficient to confer full and enduring beneficial effects. We propose that the subjective effects of psychedelics are necessary for their enduring beneficial effects and that these subjective effects account for the majority of their benefit.

Set and Setting: A Randomized Study of Different Musical Genres in Supporting Psychedelic Therapy

Mounting evidence supports the serotonin 2A receptor agonist psilocybin as a psychiatric pharmacotherapy. Little research has experimentally examined how session "set and setting" impacts subjective and therapeutic effects. We analyzed the effects of the musical genre played during sessions of a psilocybin study for tobacco smoking cessation. Participants (N = 10) received psilocybin (20-30 mg/70 kg) in two sessions, each with a different musical genre (Western classical versus overtone-based), with the order counterbalanced. Participants chose one genre for a third session (30 mg/70 kg). Mystical experiences scores tended to be higher in overtone-based sessions than in Western classical sessions. Six of ten participants chose the overtone-based music for a third session. Biologically confirmed smoking abstinence was similar based on musical choice, with a slight benefit for participants choosing the overtone-based playlist (66.7% versus 50%). These data call into question whether Western classical music typically used in psychedelic therapy holds a unique benefit. Broadly, we call for experimentally examining session components toward optimizing psychedelic therapeutic protocols.

Ethical and legal issues in psychedelic harm reduction and integration therapy

Psychedelic-assisted therapy may represent an upcoming paradigm shift in the treatment of mental health problems as recent clinical trials have demonstrated strong evidence of their therapeutic benefits. While psychedelics are currently prohibited substances in most countries, the growing popularity of their therapeutic potential is leading many people to use psychedelics on their own rather than waiting for legal medical access. Therapists therefore have an ethical duty to meet this need by providing support for clients using psychedelics. However, incorporating psychedelics into traditional psychotherapy poses some risk given their prohibited status and many therapists are unsure of how they might practice in this area. This paper explicates such risks and describes ways in which therapists can mitigate them and strive to practice within legal and ethical boundaries. A harm reduction approach will be emphasized as a useful framework for conducting therapy around clients' use of psychedelics. It is argued that therapists can meet with clients before and after their own personal psychedelic experiences in order to help clients minimize risk and maximize benefit. Common clinical scenarios in this growing clinical area will also be discussed.

Neural and subjective effects of inhaled N,N-dimethyltryptamine in natural settings

BACKGROUND

N,N-dimethyltryptamine is a short-acting psychedelic tryptamine found naturally in many plants and animals. Few studies to date have addressed the neural and psychological effects of N,N-dimethyltryptamine alone, either administered intravenously or inhaled in freebase form, and none have been conducted in natural settings.

AIMS

Our primary aim was to study the acute effects of inhaled N,N-dimethyltryptamine in natural settings, focusing on questions tuned to the advantages of conducting field research, including the effects of contextual factors (i.e. "set" and "setting"), the possibility of studying a comparatively large number of subjects, and the relaxed mental state of participants consuming N,N-dimethyltryptamine in familiar and comfortable settings.

METHODS

We combined state-of-the-art wireless electroencephalography with psychometric questionnaires to study the neural and subjective effects of naturalistic N,N-dimethyltryptamine use in 35 healthy and experienced participants.

RESULTS

We observed that N,N-dimethyltryptamine significantly decreased the power of alpha (8-12 Hz) oscillations throughout all scalp locations, while simultaneously increasing power of delta (1-4 Hz) and gamma (30-40 Hz) oscillations. Gamma power increases correlated with subjective reports indicative of some features of mystical-type experiences. N,N-dimethyltryptamine also increased global synchrony and metastability in the gamma band while decreasing those measures in the alpha band.

CONCLUSIONS

Our results are consistent with previous studies of psychedelic action in the human brain, while at the same time the results suggest potential electroencephalography markers of mystical-type experiences in natural settings, thus highlighting the importance of investigating these compounds in the contexts where they are naturally consumed.