Long-term effects of psychedelic drugs: A systematic review

Association between Lifetime Classic Psychedelic Use and Sick Leave in a Population-Based Sample

OBJECTIVES

Absenteeism from work due to illness, and related costs, has increased steadily during the past decades. In recent years, there has been a reemergence of research on the therapeutic effects of classic psychedelics showing associations with both physical and mental health. However, the association between classic psychedelics and sick leave remains unknown. The aim of this study is to investigate the association between lifetime classic psychedelic use and sick leave in the past 30 days among adults in the United States (N = 407,717), using data from the National Survey on Drug Use and Health (2005-2019), weighted to be representative of the US adult population.

METHODS

The primary analysis was conducted using multiple linear regression, controlling for sociodemographic characteristics, risky behavior, and use of other substances.

RESULTS

There was a significant and negative association between lifetime classic psychedelic use and sick leave in the past 30 days (B = -0.09, p < 0.01) when adjusting for all control variables.

CONCLUSION

These findings suggest that classic psychedelics could potentially lead to reduced sick leave and associated costs in the general population, but more research is needed to investigate potential causal pathways of classic psychedelics on sick leave and evaluate possible mechanisms.

Attitudes and Beliefs about the Therapeutic Use of Psychedelic Drugs among Psychologists in the United States

Psychologists are a vital component of mental health treatment and their perceptions of psychedelic-assisted therapy are critical for future implementation. This cross-sectional quasi-experimental electronic survey study explored the attitudes about psychedelics used in treatment among 366 clinical psychologists in the United States. Participants expressed cautiously favorable attitudes toward therapeutic psychedelic experiences but indicated concern about possible psychiatric and neurocognitive risks. Most participants indicated that they lack an understanding of the full range of effects of psychedelics, would need to seek out additional consultation, and endorsed positive beliefs in the potential of psychedelic treatment and the need for further research. Overall, this research identified the need to increase education and training about psychedelics for psychologists in order to help increase knowledge and reduce stigma about psychedelic therapies.

Comparison of psychedelic and near-death or other non-ordinary experiences in changing attitudes about death and dying

Both psychedelic drug experiences and near-death experiences can occasion changes in perspectives on death and dying, but there have been few direct comparisons of these phenomena. This study directly compared psychedelic occasioned and non-drug experiences which altered individuals’ beliefs about death. Individuals who reported an experience that altered their beliefs about death occasioned by either a psychedelic drug or a near-death or other non-ordinary experience completed an online survey. Circumstances of the experience, mystical and near-death subjective features, changes in attitudes about death, and other persisting effects were evaluated. The study sample (n = 3192) included five groups: non-drug near-death or other non-ordinary experiences (n = 933), and drug experiences occasioned by lysergic acid diethylamide (LSD) (n = 904), psilocybin (n = 766), ayahuasca (n = 282), or N,N-dimethyltryptamine (DMT) (n = 307). Analyses of differences in experiences were adjusted statistically for demographic differences between groups. Compared to the psychedelic groups, the non-drug group was more likely to report being unconscious, clinically dead, and that their life was in imminent danger. The groups were remarkably similar in the reported changes in death attitudes attributed to the experience, including a reduced fear of death and high ratings of positive persisting effects and personal meaning, spiritual significance, and psychological insight. Although both psychedelic and non-drug participants showed robust increases on standardized measures of mystical and near-death experiences, these measures were significantly greater in the psychedelic participants. Non-drug participants were more likely to rate their experiences as the single most meaningful of their lives. Comparing across psychedelic substances, ayahuasca and DMT groups tended report stronger and more positive enduring consequences of the experience than the psilocybin and LSD groups, which were largely indistinguishable. These data provide a detailed characterization and comparison of psychedelic occasioned and non-drug experiences that changed attitudes about death and suggest the importance of future prospective psychedelic administration studies.

5-HT2A SNPs Alter the Pharmacological Signaling of Potentially Therapeutic Psychedelics

Serotonin (5-hydroxytryptamine; 5-HT) 2A receptor (5-HT2AR) signaling is essential for the actions of classical psychedelic drugs. In this study, we examined whether sequence variations in the 5-HT2AR gene affect the signaling of four commonly used psychedelic drugs. We examined the in vitro pharmacology of seven non-synonymous single-nucleotide polymorphisms (SNPs), which give rise to Ser12Asn, Thr25Asn, Asp48Asn, Ile197Val^4.47, Ala230Thr, Ala447Val, and His452Tyr variant 5-HT2A serotonin receptors. We found that these non-synonymous SNPs exert statistically significant, although modest, effects on the efficacy and potency of four therapeutically relevant psychedelics. Significantly, the in vitro pharmacological effects of the SNP drug actions at 5-HT2AR are drug specific.

Naturalistic use of psychedelics is related to emotional reactivity and self-consciousness: The mediating role of ego-dissolution and mystical experiences

BACKGROUND

Psychedelics are able to acutely alter emotional reactivity and self-consciousness. However, whether the regular naturalistic use of psychedelics can be linked to more persistent trait-level changes in these domains remains an open question.

AIM

To test the hypotheses that (1) using psychedelics is related to higher positive and lower negative emotional reactivity; and (2) an adaptive pattern of self-consciousness, including diminished public self-consciousness and rumination, and increased reflection and self-awareness; and (3) these relations are mediated by the intensity of past ego-dissolution and mystical experiences.

METHOD

An online survey including questions about the history of psychoactive substance use; questionnaires measuring trait levels of emotional reactivity and self-consciousness; questionnaires for retrospective assessment of ego-dissolution and mystical experiences. Data collected from 2516 participants (1661 psychedelics users) were analyzed using robust linear regression and mediation analysis.

RESULTS

A higher number of lifetime uses of psychedelics predicted greater positive and lower negative emotional reactivity; also, in the domain of self-consciousness, it predicted greater reflection and internal state awareness, and reduced rumination tendency and public self-consciousness. Finally, the intensity of past mystical and ego-dissolution experiences mediated almost all the observed relationships between the lifetime number of psychedelics uses and psychological variables.

CONCLUSIONS

Lifetime psychedelics use predicts an adaptive pattern of trait-level emotional reactivity and self-consciousness. Ego-dissolution and mystical experiences are essential in understanding the long-lasting psychological effects of psychedelics use. Our findings might potentially explain previous observations of increased well-being in psychedelics users.

Secular Mysticism

How a positive naturalist understanding of mystical experiences is possible and how these experiences and accompanying practices can be incorporated into a secular mysticism are discussed. Philosophical issues related to such a secular mysticism are also raised: is a truly secular mysticism possible? Are mystical experiences cognitive of transcendent non-natural realities? Can secular mysticism address the issue of the possible construction of mystical experiences? Can one find meaning or a purpose to life when non-natural realities and life after death are not parts of the picture?

Defining Transformative Experiences: A Conceptual Analysis

The concept of transformative experience (TE) has been widely explored by several disciplines from philosophy to neurobiology, and in different domains, from the spiritual to the educational one. This attitude has engendered heterogeneous models to explain this phenomenon. However, a consistent and clear understanding of this construct remains elusive. The aim of this work is to provide an initial comprehensive interdisciplinary, cross-domain, up-to-date, and integrated overview on the concept of TEs. Firstly, all the models and theories on TEs were reviewed to extract and analyze TEs’ main components emerging from different disciplines. Then, this preliminary analysis was integrated with an in-depth examination of redundancies and particularities across domains and disciplines, to provide an integrated theoretical framework of TEs and a preliminary interdisciplinary operational definition of TEs. This examination, in turn, can help organize current research and theories, thus providing suggestions for operationalizing TEs as well as encouraging new interdisciplinary research endeavors.

Great Expectations: recommendations for improving the methodological rigor of psychedelic clinical trials

RATIONALE

Psychedelic research continues to garner significant public and scientific interest with a growing number of clinical studies examining a wide range of conditions and disorders. However, expectancy effects and effective condition masking have been raised as critical limitations to the interpretability of the research.

OBJECTIVE

In this article, we review the many methodological challenges of conducting psychedelic clinical trials and provide recommendations for improving the rigor of future research.

RESULTS

Although some challenges are shared with psychotherapy and pharmacology trials more broadly, psychedelic clinical trials have to contend with several unique sources of potential bias. The subjective effects of a high-dose psychedelic are often so pronounced that it is difficult to mask participants to their treatment condition; the significant hype from positive media coverage on the clinical potential of psychedelics influences participants' expectations for treatment benefit; and participant unmasking and treatment expectations can interact in such a way that makes psychedelic therapy highly susceptible to large placebo and nocebo effects. Specific recommendations to increase the success of masking procedures and reduce the influence of participant expectancies are discussed in the context of study development, participant recruitment and selection, incomplete disclosure of the study design, choice of active placebo condition, as well as the measurement of participant expectations and masking efficacy.

CONCLUSION

Incorporating the recommended design elements is intended to reduce the risk of bias in psychedelic clinical trials and thereby increases the ability to discern treatment-specific effects of psychedelic therapy.

Psychedelic Mystical Experience: A New Agenda for Theology

When the link between psychedelic drugs and mystical states of experience was first discovered in the 1960s, Huston Smith challenged scholars in religion and philosophy to consider the implications. Very few took up his challenge. Beginning in 2006, hundreds of studies have linked psychedelics not just to mystical states of experience but to potential treatments for many mental health disorders. Regulatory approval for therapies is on the horizon, and hundreds of millions of people worldwide could be treated. Research findings challenge the underlying rationale of the War on Drugs, leading to decriminalization of specific psychedelic drugs or to authorization of their use in mental health contexts. Religious institutions are slowly adapting, with some referring to psychedelics as sacraments or as pathways to deeper spirituality. Religious leaders are also beginning to speak out publicly in support of careful use of these drugs, and some are training to become “psychedelic chaplains” to work alongside mental health professionals administering these drugs. Scholars in theology and religion are encouraged to engage these trends, to explore challenging philosophical and theological issues surrounding mystical states of experience in general, and to consider the long-term cultural impact of the most recent psychedelic research.

Psychedelic Experiences and Mindfulness are Associated with Improved Wellbeing

Both psychedelics and mindfulness are recently emerging topics of interest in academia and popular culture. The Prevalence of personal meditation practices and recreational psychedelic use has consistently increased in the past decade. While clinical work has shown both to improve long-term wellbeing, data on naturalistic applications of psychedelics and mindfulness are lacking. The current study examined the relationship between psychedelic use, mindfulness, and multi-faceted wellbeing as an outcome. Hierarchical regression was used to quantify these associations on a sample of people (N = 1,219) who engage in both meditation practices and psychedelic use. Results show that both mindfulness and mystical experiences are associated with substantial increases in wellbeing. Psychedelics were found to be a moderator of the relationship between mystical experience wellbeing. These data are among the first to establish a strong relationship between personal mindfulness practice, recreational psychedelic use, and overall psychological wellbeing in a naturalistic framework.

Validation of a French Version of the Mystical Experience Questionnaire with Retrospective Reports of the Most Significant Psychedelic Experience among French Users

Mystical experiences triggered by psychedelic drugs predict symptom reduction in various psychiatric disorders, and increased well-being in healthy individuals. This work aimed at validating a French version of a tool used to measure mystical experiences: the Revised Mystical Experience Questionnaire-30 items (MEQ30). Construct validity, internal consistencies, concurrent, discriminant, and predictive validities of the French MEQ30 were examined using data about the most significant psychedelic experience of 320 French individuals. Results showed that the original four-factor (i.e., mystical, positive mood, transcendence, and ineffability) structure fit the data best, with good to excellent statistical indices. Total French MEQ30 score was strongly associated with subjective ratings of the mystical (i.e., mystical, spiritual, or religious, and personally significant) and drug intensity-related qualities of the experience, but not with non-mystical (i.e., fun, inebriating, and easy) qualities. Moreover, French MEQ30 score was a significant predictor of subjective positive changes in psychological well-being, relations with self and others, feeling of proximity or connection with nature, and creativity, whereas drug intensity-related and non-mystical qualities of the experience were not, or were only weakly associated with such changes. This French version of the MEQ30 seems to be an appropriate tool for measuring mystical experiences among French speaking individuals.

Adverse effects of psychedelics: From anecdotes and misinformation to systematic science

BACKGROUND

Despite an increasing body of research highlighting their efficacy to treat a broad range of medical conditions, psychedelic drugs remain a controversial issue among the public and politicians, tainted by previous stigmatisation and perceptions of risk and danger.

OBJECTIVE

This narrative review examines the evidence for potential harms of the classic psychedelics by separating anecdotes and misinformation from systematic research.

METHODS

Taking a high-level perspective, we address both psychological and psychiatric risks, such as abuse liability and potential for dependence, as well as medical harms, including toxicity and overdose. We explore the evidence base for these adverse effects to elucidate which of these harms are based largely on anecdotes versus those that stand up to current scientific scrutiny.

RESULTS

Our review shows that medical risks are often minimal, and that many - albeit not all - of the persistent negative perceptions of psychological risks are unsupported by the currently available scientific evidence, with the majority of reported adverse effects not being observed in a regulated and/or medical context.

CONCLUSIONS

This highlights the importance for clinicians and therapists to keep to the highest safety and ethical standards. It is imperative not to be overzealous and to ensure balanced media reporting to avoid future controversies, so that much needed research can continue.

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.

The economics of psychedelic-assisted therapies: A research agenda

After a long hiatus, psychiatry is undergoing a resurgence of interest in psychedelic drugs as therapy for a wide range of mental health disorders Accumulating clinical evidence suggests substantial potential for psychedelics used in a therapeutic context, as treatment for, among other disorders, depression, post-traumatic stress disorder (PTSD), and addictions to tobacco, opioids and alcohol. As soon as 2024, powerful new therapeutic modalities could become available for individuals with mental health problems refractory to traditional therapies. Yet research has lagged on economic considerations, such as costs and cost-effectiveness, the economic effects of widespread implementation, pricing, and economic appraisal's methodological considerations relevant to psychedelic therapies. These issues are critical if psychedelic therapies are to become widely accessible. We describe six types of economic analyses and their rationale for decisions and planning including the needs of health care payers. We also outline desirable features of this research, including scientific rigor, long horizons, equity, and a global view.

Validation of the Psychological Insight Scale: A new scale to assess psychological insight following a psychedelic experience

INTRODUCTION

As their name suggests, 'psychedelic' (mind-revealing) compounds are thought to catalyse processes of psychological insight; however, few satisfactory scales exist to sample this. This study sought to develop a new scale to measure psychological insight after a psychedelic experience: the Psychological Insight Scale (PIS).

METHODS

The PIS is a six- to seven-item questionnaire that enquires about psychological insight after a psychedelic experience (PIS-6) and accompanied behavioural changes (PIS item 7). In total, 886 participants took part in a study in which the PIS and other questionnaires were completed in a prospective fashion in relation to a planned psychedelic experience. For validation purposes, data from 279 participants were analysed from a non-specific 'global psychedelic survey' study.

RESULTS

Principal components analysis of PIS scores revealed a principal component explaining 73.57% of the variance, which displayed high internal consistency at multiple timepoints throughout the study (average Cronbach's α = 0.94). Criterion validity was confirmed using the global psychedelic survey study, and convergent validity was confirmed via the Therapeutic-Realizations Scale. Furthermore, PIS scores significantly mediated the relationship between emotional breakthrough and long-term well-being.

CONCLUSION

The PIS is complementary to current subjective measures used in psychedelic studies, most of which are completed in relation to the acute experience. Insight - as measured by the PIS - was found to be a key mediator of long-term psychological outcomes following a psychedelic experience. Future research may investigate how insight varies throughout a psychedelic process, its underlying neurobiology and how it impacts behaviour and mental health.

Medicinal psychedelics for mental health and addiction: Advancing research of an emerging paradigm

The medical use of psychedelic substances (e.g. psilocybin, ayahuasca, lysergic acid diethylamide and 3,4-methylenedioxymethamphetamine) is attracting renewed interest, driven by a pressing need for research and development of novel therapies for psychiatric disorders, as well as promising results of contemporary studies. In this Viewpoint, we reflect upon the 'Clinical Memorandum on Psychedelics' recently released by the Royal Australian and New Zealand College of Psychiatrists and note subsequent developments including the application for down-scheduling of psilocybin and 3,4-methylenedioxymethamphetamine presently being considered by the Therapeutic Goods Administration and approvals for access via the Special Access Scheme. We suggest that this field is worthy of rigorous research to assess potential benefits, address safety parameters and clarify therapeutic mechanisms. To this end, we outline recent research findings, provide an overview of current knowledge relating to mechanisms of action and discuss salient aspects of the psychedelic-assisted psychotherapy treatment model. The sum of this research points towards medicinal psychedelics as a potential new class of psychiatric treatments when used within a medically supervised framework with integrated psychotherapeutic support. However, before widespread translation into clinical use can occur, appropriately designed and sufficiently powered trials are required to detect both potential positive and negative outcomes. Unique safety and regulatory challenges also need to be addressed. As for any new medical therapy, psychedelic research needs to be conducted in a rigorous manner, through the dispassionate lens of scientific enquiry. Carte blanche availability to practitioners, without specific protocols and appropriate training, would be potentially harmful to individuals and detrimental to the field.

Psychedelics and hallucinogens in Psychiatry: finding new pharmacological targets

BACKGROUND

The therapeutic options for neurobehavioral disorders are still limited, and in many cases, they lack a satisfactory balance between efficacy and side effects.

OBJECTIVE

This work aims to review current evidence regarding the potential contribution of psychedelics and hallucinogens to the discovery of new drugs for treating different psychiatric disorders.

DISCUSSION

Ayahuasca/N,N-dimethyltryptamine (DMT), lysergic acid diethylamide (LSD), and psilocybin have evidence supporting their use in depression, and psilocybin and ayahuasca have also shown good results in treatment-resistant depression. In randomized controlled trials (RCTs) conducted with anxious patients, there were symptomatic improvements with psilocybin and LSD. Psilocybin diminished Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores in a small obsessive-compulsive disorder (OCD) sample. The evidence is less robust regarding substance use disorders, but it suggests a possible role for LSD and psilocybin in alcohol use disorders and for psilocybin in tobacco addiction. In a clinical setting, these substances seem to be safe and well-tolerated. Their mechanisms of action are not fully elucidated, but there seems to be a preponderant role of 5-hydroxytryptamine (5HT) 2A agonism, as well as connectivity changes within the default mode network (DMN) and amygdala and some other molecular modifications.

CONCLUSION

The studies underlying the conclusions have small samples and are heterogeneous in their methods. However, the results suggest that the use of psychedelics and hallucinogens could be considered in some disorders. More studies are needed to reinforce their evidence as potential new drugs.

Hallucinogen Use and Misuse in Older Adults

Hallucinogens, or psychedelics, are substances/drugs that have been used for over a millennium. The most well known are LSD, psilocybin, mescaline, and PCP. These substances may induce hallucinations as well as cause somatic and psychological symptoms. Because of the Controlled Substances Act of 1970, there has been very little research done to determine the long-term consequences or perhaps potential benefit of misuse and abuse of hallucinogens. Typically, these drugs are not abused but more often misused. Recently, there has been a renewed interest in these compounds, which may lead to possible therapeutic options.

Rediscovering Psilocybin as an Antidepressive Treatment Strategy

There has recently been a renewal of interest in psychedelic research on the use of psilocybin in psychiatric treatment and, in particular, for the treatment of major depressive disorder (MDD). Several state-of-the-art studies have provided new insight into the mechanisms of action of psilocybin and its therapeutic potential. Nevertheless, many questions remain unanswered. With this review, we provide an overview of the current state of research on the potential mechanisms of psilocybin, its antidepressant potential, and the associated risks and adverse effects, to provide an update on a controversial topic discussed in psychopharmacology. A database search was conducted in Medline including articles on psilocybin over the period of the last 20 years. Despite the promising progress in understanding the mechanisms of psilocybin, the exact antidepressive mechanism and the role of the psychedelic experience remain elusive. The studies included in this review found high treatment effect sizes for psilocybin as an antidepressant. However, the results must be regarded as preliminary due to several limitations. Although the current studies observed no severe adverse events, several questions regarding safety and utility remain and must be subject of future research.

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.

Neuropsychological Functioning in Users of Serotonergic Psychedelics - A Systematic Review and Meta-Analysis

Background: Serotonergic psychedelics (SPs) like LSD, psilocybin, DMT, and mescaline are a heterogeneous group of substances that share agonism at 5-HT2a receptors. Besides the ability of these substances to facilitate profoundly altered states of consciousness, persisting psychological effects have been reported after single administrations, which outlast the acute psychedelic effects. In this review and meta-analysis, we investigated if repeated SP use associates with a characteristic neuropsychological profile indicating persisting effects on neuropsychological function. Methods: We conducted a systematic review of studies investigating the neuropsychological performance in SP users, searching studies in Medline, Web of Science, embase, ClinicalTrials.gov, and EudraCT. Studies were included if they reported at least one neuropsychological measurement in users of SPs. Studies comparing SP users and non-users that reported mean scores and standard deviations were included in an exploratory meta-analysis. Results: 13 studies (N = 539) published between 1969 and 2020 were included in this systematic review. Overall, we found that only three SPs were specifically investigated: ayahuasca (6 studies, n = 343), LSD (5 studies, n = 135), and peyote (1 study, n = 61). However, heterogeneity of the methodological quality was high across studies, with matching problems representing the most important limitation. Across all SPs, no uniform pattern of neuropsychological impairment was identified. Rather, the individual SPs seemed to be associated with distinct neuropsychological profiles. For instance, one study (n = 42) found LSD users to perform worse in trials A and B of the Trail-Making task, whereas meta-analytic assessment (5 studies, n = 352) of eleven individual neuropsychological measures indicated a better performance of ayahuasca users in the Stroop incongruent task (p = 0.03) and no differences in the others (all p > 0.05). Conclusion: The majority of the included studies were not completely successful in controlling for confounders such as differences in non-psychedelic substance use between SP-users and non-users. Our analysis suggests that LSD, ayahuasca and peyote may have different neuropsychological consequences associated with their use. While LSD users showed reduced executive functioning and peyote users showed no differences across domains, there is some evidence that ayahuasca use is associated with increased executive functioning.

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.

Spiritual Benefit from Cannabis

Like many mind-altering plants, cannabis has been part of spiritual practices for thousands of years. It has deep roots in Hinduism, Islam, Rastafarianism, and indigenous traditions in Asia, Africa, and elsewhere. Yet almost no attention has been given to how contemporary adults employ it spiritually. A sample of 1087 participants (mean age = 38.9) completed an online survey assessing their use of cannabis and other substances, as well as spiritual and psychological characteristics. Spiritual benefit from cannabis was reported by 66.1% of the sample, and 5.5% reported it had sometimes been a spiritual hindrance. A MANOVA showed that those who reported spiritual benefit differed significantly from those who did not on several outcome variables, and a post hoc descriptive discriminant analysis revealed that expansiveness motivation, non-theistic daily spiritual experience, meditation frequency, and two mindfulness facets contributed most to differentiating the two groups. The majority of the sample (63%) was free of cannabis use disorder. Compared to disordered groups, the non-disordered group was significantly older and scored lower on experiential avoidance, psychological distress, and several motives for use. Results suggest that spiritual motives for cannabis use may be widespread. Implications for future research on spiritual use of cannabis are discussed.

The Potential Role of Psychedelic Drugs in Mental Health Care of the Future

Serotonergic psychedelics such as psilocybin, lysergic acid diethylamide (LSD), or dimethyltryptamine (DMT), as well as psychoactive drugs that trigger phenomenologically- related experiences like 3,4-methylenedioxymethamphetamine (MDMA) and ketamine, belong to the most promising treatment approaches in contemporary psychiatry. Psychedelic-assisted psychotherapy is not only a new treatment paradigm in psychopharmacology, but it also requires a redefinition of psychotherapeutic processes and the contextualization of psychopharmacological interventions within a new treatment infrastructure. Crucial for future practice and research in the field are (1) informed patient referral and co-treatment practices, (2) screening (e. g., choosing the right patients for these therapies), (3) the dosing preparation sessions, (4) the assisted dosing sessions as well as after-care procedures such as (5) psychological integration and (6) supporting the development of structured patient communities. Definition of future treatment delivery infrastructures and requirements for therapist training are further challenges for research and practice. Finally, the implementation of psychedelic-assisted psychotherapy in routine mental health care must be embedded into public communication about the potential and risks of these innovative therapeutic approaches. This paper provides a synopsis of challenges for practitioners, researchers, and regulators to be addressed in the approval processes of psychedelics.

Predicting Reactions to Psychedelic Drugs: A Systematic Review of States and Traits Related to Acute Drug Effects

Psychedelic drugs are increasingly being incorporated into therapeutic contexts for the purposes of promoting mental health. However, they can also induce adverse reactions in some individuals, and it is difficult to predict before treatment who is likely to experience positive or adverse acute effects. Although consideration of setting and dosage as well as excluding individuals with psychotic predispositions has thus far led to a high degree of safety, it is imperative that researchers develop a more nuanced understanding of how to predict individual reactions. To this end, the current systematic review coalesced the results of 14 studies that included baseline states or traits predictive of the acute effects of psychedelics. Individuals high in the traits of absorption, openness, and acceptance as well as a state of surrender were more likely to have positive and mystical-type experiences, whereas those low in openness and surrender or in preoccupied, apprehensive, or confused psychological states were more likely to experience acute adverse reactions. Participant sex was not a robust predictor of drug effects, but 5-HT2AR binding potential, executive network node diversity, and rACC volume may be potential baseline biomarkers related to acute reactions. Finally, increased age and experience with psychedelics were individual differences related to generally less intense effects, indicating that users may become slightly less sensitive to the effects of the drugs after repeated usage. Although future well-powered, placebo-controlled trials directly comparing the relative importance of these predictors is needed, this review synthesizes the field's current understanding of how to predict acute reactions to psychedelic drugs.

Spontaneous and deliberate creative cognition during and after psilocybin exposure

Creativity is an essential cognitive ability linked to all areas of our everyday functioning. Thus, finding a way to enhance it is of broad interest. A large number of anecdotal reports suggest that the consumption of psychedelic drugs can enhance creative thinking; however, scientific evidence is lacking. Following a double-blind, placebo-controlled, parallel-group design, we demonstrated that psilocybin (0.17 mg/kg) induced a time- and construct-related differentiation of effects on creative thinking. Acutely, psilocybin increased ratings of (spontaneous) creative insights, while decreasing (deliberate) task-based creativity. Seven days after psilocybin, number of novel ideas increased. Furthermore, we utilized an ultrahigh field multimodal brain imaging approach, and found that acute and persisting effects were predicted by within- and between-network connectivity of the default mode network. Findings add some support to historical claims that psychedelics can influence aspects of the creative process, potentially indicating them as a tool to investigate creativity and subsequent underlying neural mechanisms. Trial NL6007; psilocybin as a tool for enhanced cognitive flexibility; https://www.trialregister.nl/trial/6007 .

Associations between lifetime classic psychedelic use and markers of physical health

BACKGROUND

In recent years, there has been significant research on the mental health effects of classic psychedelic use, but there is very little evidence on how classic psychedelics might influence physical health.

AIMS

The purpose of the present study was to investigate the associations between lifetime classic psychedelic use and markers of physical health.

METHODS

Using data from the National Survey on Drug Use and Health (2015-2018) with 171,766 (unweighted) adults aged 18 or above in the United States, the current study examined the associations between lifetime classic psychedelic use and three markers of physical health (self-reported overall health, body mass index, and heart condition and/or cancer in the past 12 months) while controlling for a range of covariates.

RESULTS

Respondents who reported having tried a classic psychedelic at least once in their lifetime had significantly higher odds of greater self-reported overall health and significantly lower odds of being overweight or obese versus having a normal weight. The association between lifetime classic psychedelic use and having a heart condition and/or cancer in the past 12 months approached conventional levels of significance, with lower odds of having a heart condition and/or cancer in the past 12 months for respondents who had tried a classic psychedelic at least once.

CONCLUSION

The results of the present study suggest that classic psychedelics may be beneficial to physical health. Future research should investigate the causal effects of classic psychedelics on physical health and evaluate possible mechanisms.

Combining Psychedelic and Mindfulness Interventions: Synergies to Inform Clinical Practice

Psychedelic and mindfulness interventions have been shown to improve mental ill-health and wellbeing, with a range of clinical processes and effects in common. However, each appear to contain specific challenges in the context of mental health treatment. In this Perspective, we focus on a set of distinct affordances, "useful differences", within psychedelic and mindfulness interventions that might address common challenges within the other intervention. Accordingly, we propose a set of applied synergies, indicating specific ways in which these two promising interventions might be combined for greater benefit. Metaphorically, on the journey toward mental health and wellbeing, we propose that psychedelic treatments may serve the role of Compass (initiating, motivating, and steering the course of mindfulness practice), with mindfulness interventions serving the role of Vehicle (integrating, deepening, generalizing, and maintaining the novel perspectives and motivation instigated by psychedelic experience). We outline a set of testable hypotheses and future research associated with the synergistic action of psychedelic and mindfulness interventions toward improved clinical outcomes.

Psychedelic drugs and perception: a narrative review of the first era of research

Psychedelic drugs are well-known for transiently altering perception, and in particular, for their visual effects. Although scientific interest into the substances' effects on perception increased during the first era of psychedelic research during the early to mid-20th century, there is currently no source where these findings have been synthesized. In addressing this gap, the current narrative review found that psychedelics were examined for their influences across all levels of the visual system (e.g., retinal, cortical, subcortical, simple visual processing, complex imagery, hallucinations). Psychedelics were also shown to affect auditory discrimination/generalization, neural correlates of auditory processing, and led to auditory hallucinations in subsets of participants. Several studies demonstrated that psychedelics can distort representations of body schema and time perception. Concerns regarding methodological standards of this era are a limitation to the findings and are discussed. Collectively, this review preserves and increases the accessibility of the work done by pioneering psychedelic/perception researchers, synthesizes findings, and critically analyzes areas of discrepancy to inform future studies.

Psychedelic Psychiatry and the Consult-Liaison Psychiatrist: A Primer

BACKGROUND

Psychedelic compounds such as lysergic acid diethylamide (LSD), psilocybin, and 3,4-Methylenedioxymethamphetamine (MDMA) share a long and complex history with psychiatry. A half century ago, psychedelics were widely employed by psychiatrists in investigational and clinical settings, with studies demonstrating promising findings for their use in the treatment of mental illness and substance use disorders. However, concerns were also raised about their abuse potential and other adverse effects. Owing to these worries and psychedelics' association with the counterculture movement, psychedelics were largely outlawed in the United States in 1970, bringing research on their therapeutic potential to a halt. However, in recent years, a resurgence of psychedelic research has revealed compelling, though early, evidence for the use of psychedelic-assisted therapy in treating alcohol use disorder, nicotine use disorder, posttraumatic stress disorder, and depression.

OBJECTIVE

Here we provide an overview of psychiatry's complicated relationship with psychedelics, while reviewing contemporary findings on psychedelic-assisted therapy, safety of psychedelic-assisted therapy, and risks of nonmedical use. We also make the case that psychiatry should consider preparing now for the possibility of Food and Drug Administration approval of psychedelic-assisted therapies in the near future. We conclude by discussing how growing societal interest in psychedelics could impact the work of consult-liaison psychiatrists, while also exploring how consult-liaison psychiatrists might contribute to future delivery of psychedelic treatments.

METHODS

We reviewed literature on psychedelic-assisted therapies and adverse events resulting from nonmedical psychedelic use.

RESULTS

We found a small, but rapidly growing literature indicating that psychedelic-assisted therapies may have treatment potential for mental illness and addiction. Our search also revealed a variety of rare adverse events stemming from nonmedical psychedelic use.

CONCLUSIONS

Despite past concerns about psychedelics, current data indicate psychedelic-assisted therapy may potentially reduce suffering owing to mental illness and addiction if administered thoughtfully and cautiously by trained professionals in medical settings.

Baseline Power of Theta Oscillations Predicts Mystical-Type Experiences Induced by DMT in a Natural Setting

N,N-Dimethyltryptamine (DMT) is a classic psychedelic capable of inducing short-lasting but profound changes in consciousness. As with other psychedelics, the experience induced by DMT strongly depends upon contextual factors, yet the neurobiological determinants of this variability remain unknown. The present study investigated changes in neural oscillations elicited by inhaled DMT, and whether baseline electroencephalography (EEG) recordings could predict the subjective effects reported by the participants. Healthy volunteers (N = 35) were measured with EEG before and during the acute effects of DMT consumed in a natural setting. Source-localized neural oscillations were correlated with the results of multiple questionnaires employed to assess the subjective effects of the drug. DMT resulted in a marked reduction of alpha and beta oscillations, and increased posterior spectral power in the delta, theta and gamma bands. The power of fronto-temporal theta oscillations was inversely correlated with scales indexing feelings of unity and transcendence, which are an integral part of the phenomenology of mystical-type experiences. The robustness of these results was supported using a machine learning model for regression trained and tested following a cross-validation procedure. These results are consistent with the observation that the state of mind prior to consuming a psychedelic drug influences the ensuing subjective experience of the user. They also suggest that baseline EEG screenings before administration of a serotonergic psychedelic could be useful to estimate the likelihood of inducing mystical-type experiences, previously linked to sustained positive effects in well-being and improved outcome of therapeutic interventions.

Synthesis and Characterization of 5-MeO-DMT Succinate for Clinical Use

To support clinical use, a multigram-scale process has been developed to provide 5-MeO-DMT, a psychedelic natural product found in the parotid gland secretions of the toad, Incilius alvarius. Several synthetic routes were initially explored, and the selected process featured an optimized Fischer indole reaction to 5-MeO-DMT freebase in high-yield, from which the 1:1 succinate salt was produced to provide 136 g of crystalline active pharmaceutical ingredient (API) with 99.86% peak area by high-performance liquid chromatography (HPLC) and a net yield of 49%. The report provides in-process monitoring, validated analytical methods, impurity formation and removal, and solid-state characterization of the API essential for subsequent clinical development.

The potential synergistic effects between psychedelic administration and nature contact for the improvement of mental health

Therapeutic psychedelic administration and contact with nature have been associated with the same psychological mechanisms: decreased rumination and negative affect, enhanced psychological connectedness and mindfulness-related capacities, and heightened states of awe and transcendent experiences, all processes linked to improvements in mental health amongst clinical and healthy populations. Nature-based settings can have inherently psychologically soothing properties which may complement all stages of psychedelic therapy (mainly preparation and integration) whilst potentiating increases in nature relatedness, with associated psychological benefits. Maximising enhancement of nature relatedness through therapeutic psychedelic administration may constitute an independent and complementary pathway towards improvements in mental health that can be elicited by psychedelics.

Post-acute psychological effects of classical serotonergic psychedelics: a systematic review and meta-analysis

BACKGROUND

Scientific interest in the therapeutic effects of classical psychedelics has increased in the past two decades. The psychological effects of these substances outside the period of acute intoxication have not been fully characterized. This study aimed to: (1) quantify the effects of psilocybin, ayahuasca, and lysergic acid diethylamide (LSD) on psychological outcomes in the post-acute period; (2) test moderators of these effects; and (3) evaluate adverse effects and risk of bias.

METHODS

We conducted a systematic review and meta-analysis of experimental studies (single-group pre-post or randomized controlled trials) that involved administration of psilocybin, ayahuasca, or LSD to clinical or non-clinical samples and assessed psychological outcomes ⩾24 h post-administration. Effects were summarized by study design, timepoint, and outcome domain.

RESULTS

A total of 34 studies (24 unique samples, n = 549, mean longest follow-up = 55.34 weeks) were included. Classical psychedelics showed significant within-group pre-post and between-group placebo-controlled effects on a range of outcomes including targeted symptoms within psychiatric samples, negative and positive affect-related measures, social outcomes, and existential/spiritual outcomes, with large between-group effect in these domains (Hedges' gs = 0.84 to 1.08). Moderator tests suggest some effects may be larger in clinical samples. Evidence of effects on big five personality traits and mindfulness was weak. There was no evidence of post-acute adverse effects.

CONCLUSIONS

High risk of bias in several domains, heterogeneity across studies, and indications of publication bias for some models highlight the need for careful, large-scale, placebo-controlled randomized trials.

Upward spirals of positive emotions and religious behaviors

Positive emotions feel good and build psychological, social, and biological resources (Broaden-and-Build Theory, Fredrickson, 1998, 2013). People who identify as religious or spiritual value them and report feeling them frequently. They are also prevalent in religious and spiritual practices, such as prayer, meditation, and collective worship. We review the literature on the reciprocal relationship between positive emotions and religion/spirituality and identify individual differences predicting greater positive emotions derived from engaging in religious practices. We suggest that beyond building religious/spiritual people's well-being, positive emotions play a role in sustaining otherwise costly religious behaviors. We integrate our review in the proposed Upward Spiral Theory of Sustained Religious Practice.

Transient Stimulation with Psychoplastogens Is Sufficient to Initiate Neuronal Growth

Cortical neuron atrophy is a hallmark of depression and includes neurite retraction, dendritic spine loss, and decreased synaptic density. Psychoplastogens, small molecules capable of rapidly promoting cortical neuron growth, have been hypothesized to produce long-lasting positive effects on behavior by rectifying these deleterious structural and functional changes. Here we demonstrate that ketamine and LSD, psychoplastogens from two structurally distinct chemical classes, promote sustained growth of cortical neurons after only short periods of stimulation. Furthermore, we show that psychoplastogen-induced cortical neuron growth can be divided into two distinct epochs: an initial stimulation phase requiring TrkB activation and a growth period involving sustained mTOR and AMPA receptor activation. Our results provide important temporal details concerning the molecular mechanisms by which next-generation antidepressants produce persistent changes in cortical neuron structure, and they suggest that rapidly excreted psychoplastogens might still be effective neurotherapeutics with unique advantages over compounds like ketamine and LSD.

The therapeutic potential of microdosing psychedelics in depression

Microdosing psychedelics is the repeated use of small doses of, for example, lysergic acid diethylamide (LSD) and psilocybin, typically for a few weeks. Despite the popular and scientific attention in recent years, and claims by users that it has therapeutic value in affective disorders like depression, little scientific knowledge is available to back this. The purpose of this review was to investigate whether there are scientific grounds to state that this practice could be helpful in the treatment of affective disorders, and safe to use repeatedly. To that end, the literature (PubMed, MedLine) was searched, looking for (controlled) experimental studies with low doses of LSD and/or psilocybin, in healthy volunteers and patient samples. After a selection process and the addition of relevant articles, 14 experimental studies entered this review. Findings show that both LSD (10-20 mcg) and psilocybin (<1-3 mg) have subtle (positive) effects on cognitive processes (time perception, convergent and divergent thinking) and brain regions involved in affective processes. Besides the pleasant experience, increased anxiety and a cycling pattern of depressive and euphoric mood were also found. With regard to safety, it was demonstrated that low doses are well tolerated (in healthy volunteers) and have no-to-minimal effects on physiological measures. While it is yet unclear whether psychedelic microdosing is of therapeutic value for depression, the aforementioned effects on selective processes suggest that low doses of psychedelics could play a role in depression by inducing some kind of cognitive flexibility, which might lead to decreased rumination. While previous studies were conducted mostly in small samples of healthy volunteers, future placebo-controlled clinical trials in depressed patients are required to understand the therapeutic value of microdosing psychedelics, how this differs from therapy using full psychedelic doses, and whether different psychedelics have different effect patterns. The proposed research will give new insights into the potential of future alternative psychiatric treatment forms that are fiercely needed.

Psychedelics and virtual reality: parallels and applications

Psychedelic drugs and virtual reality (VR) each have the capacity to disrupt the rigidity and limitations of typical conscious experience. This article delineates the parallels among psychedelic and VR states as well as their potential synergistic applications in clinical and recreational settings. Findings indicate that, individually, psychedelics and VR are used in analogous ways to alter sensory experience and evoke awe. They are also both used in tandem with traditional therapies to treat a variety of mood disorders; their shared capacity to transiently alter perspective and disrupt rigid patterns of mental experience may underly their analogous and transdiagnostic therapeutic uses. In terms of their combined applications, a number of recreational users currently utilize psychedelics and VR together to enhance their experience. We propose that VR may be a useful tool for preparing hallucinogen-naïve participants in clinical trials for the sensory distortions experienced in psychedelic states. Given the critical role of "setting" in psychedelic treatment outcomes, we also detail how VR could be used to optimize the environment in psychedelic sessions. Finally, we provide considerations for future studies and detail how advancements in psychedelic and VR research can inform one another. Collectively, this article outlines a number of connections between psychedelics and VR, and, more broadly, is representative of growing scientific interest into the interactions among technology, psychopharmacology, and mental health.