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

New psychoactive Substances: A Canadian perspective on emerging trends and challenges for the clinical laboratory

The production and use of New Psychoactive Substances (NPS) has skyrocketed over the last decade, causing major challenges for government authorities, public health agencies, and laboratories across the world. NPS are designed to mimic the psychoactive effects of unregulated or controlled drugs, while constantly being modified to evade drug control regulation. Hence, they are referred to as "legal highs", as they are technically legal to sell, possess, and use. NPS can be classified by their pharmacological mechanism of action and include cannabimimetic, depressants, dissociatives, hallucinogens, opioids, and stimulants. There is significant structural diversity within each NPS class, leading to variable detection using traditional clinical laboratory testing and complicating the interpretation of results. In this article, we review each of the NPS classes and summarize their associated mechanism of action, common structures, and metabolic pathways, and provide examples of recent drugs and emerging threats with a focus on Canadian drug trends. We also explore the current analytical advantages and limitations commonly faced by the clinical laboratory and provide insight on how toxicosurveillance can improve detection of NPS in the ever-changing NPS landscape.

Validation of the Swiss Psychedelic Side Effects Inventory: Standardized assessment of adverse effects in studies of psychedelics and MDMA

INTRODUCTION

Studies of psychedelic-assisted therapy with LSD, psilocybin, MDMA, and related substances show clinical promise but inadequately assess side effects. Measuring side effects is challenging because they are not always easily differentiated from treatment effects or disease symptoms and show high heterogeneity, variable duration and impact, and sensitivity to context. A systematic questionnaire describing important characteristics of side effects of psychedelics and MDMA would greatly improve on previous methods. We aimed to create a standardized tool for recording clinically relevant side effects of psychedelics and MDMA, including their severity, duration, impact, and treatment-relatedness.

METHODS

We constructed the Swiss Psychedelic Side Effects Inventory (SPSI) based on insights from previous research. It was pilot tested in 145 participants from three studies. Structured feedback from an expert panel was used to improve validity and feasibility.

RESULTS

The final SPSI contains 32 side effects and standardized follow-up questions about their severity, impact, treatment-relatedness, and duration. It is compatible with any study design and can be administered as an interview or self-report at any timepoint after treatment with psychedelics or MDMA.

LIMITATIONS

The SPSI omits relatively unimportant side effects for brevity's sake, though space for additional symptoms is given. Future studies are needed to confirm its validity in different contexts.

CONCLUSIONS

The SPSI is available in English and German for collecting systematic data on side effects from psychedelics and MDMA. This information is vital for improving clinical decisions, informed consent, and patient safety.

Attitudes of European psychiatrists on psychedelics: a cross-sectional survey study

Research and public interest in psychedelic-assisted psychotherapy (PAP) are growing. This study investigated attitudes toward psychedelics among a diverse and multinational sample of psychiatrists currently working in Europe. We conducted an anonymous, web-based survey consisting of demographic information, a test of basic knowledge on psychedelics, and the previously validated 20-item Attitudes on Psychedelics Questionnaire (APQ), which was validated for the first time in English within this sample. We included N = 419 participants from 33 countries in the study. One-third of participants (34%) reported past use of psychedelics. The APQ sub-scale with the highest score was Openness to Psychedelics, while Risk Assessment of Psychedelics was rated lowest. Regression modelling, explaining 31.3% of variance in APQ scores, showed that younger male psychiatrists who identified as spiritual, were better at recognizing and classifying substances as psychedelics and had previously used psychedelics had more positive attitudes on psychedelics. No professional variables besides self-reported previous experience with PAP or psychedelic research predicted APQ scores. European psychiatrists, therefore, show a general openness to psychedelics and PAP, but are concerned by the potential risks associated with them. Our findings overall suggest that psychedelics are a subject where it is difficult to remain impartial. Protocol registration: The study was pre-registered at the Open Science Framework (available online at https://osf.io/upkv3 ).

Psilocybin and chronic neuropathic pain: a systematic review

BACKGROUND/IMPORTANCE

Chronic pain affects many people globally, requiring alternative management strategies. Psilocybin is gaining attention for its potential in chronic pain management despite being classified as Schedule I.

OBJECTIVE

This systematic review critically evaluates the evidence for psilocybin, a Schedule I substance, in the treatment of chronic pain. The exact purpose of the review is to assess the impact of psilocybin on chronic pain relief, focusing on dosing protocols, treated conditions, and patient outcomes.

EVIDENCE REVIEW

A comprehensive review of PubMed, CINAHL, Web of Science, Cochrane Library, and EMBASE was conducted up to January 2024. Eligibility criteria included studies evaluating psilocybin for chronic pain management. The risk of bias was assessed using the MASTER (MethodologicAl STandards for Epidemiological Research) scale, and the strength of evidence was graded using GRADE (Grading of Recommendations, Assessment, Development, and Evaluation).

FINDINGS

The review identified 28 relevant studies focusing on dosing, treated conditions, and outcomes. The majority of the included studies (76.2%) were of low or very low quality. Several studies with moderate-to-low-quality evidence utilized a 0.14 mg/kg dosing protocol. The findings suggest promise for the use of psilocybin in chronic pain relief, though the quality of evidence is generally low.

CONCLUSIONS

The current research shows potential for psilocybin as a treatment option for chronic pain relief. However, methodological issues and a lack of high-quality evidence underscore the need for further investigations with standardized protocols. Despite these limitations, the potential for psilocybin in chronic pain management is encouraging.

PROSPERO REGISTRATION NUMBER

CRD42023493823.

Naturalistic use of psychedelics does not modulate processing of self-related stimuli (but it might modulate attentional mechanisms): An event-related potentials study

Classic psychedelics are able to profoundly alter the state of consciousness and lead to acute experiences of ego dissolution - the blurring of the distinction between representations of self and the external world. However, whether repeated use of psychedelics is associated with more prolonged and permanent modifications to the concept of self remains to be investigated. Therefore, we conducted a preregistered, cross-sectional study in which experienced psychedelics users (15 or more lifetime experiences with psychedelics; N = 56) were compared to nonusers (N = 57) in terms of neural reactivity to a Self-name (i.e., each participant's own name) stimulus, which is known to robustly activate a representation of self. Two control stimuli were additionally used: an Other-name stimulus, as a passive control condition in which no reaction was required, and a Target-name stimulus, to which participants provided a manual response and which thus constituted an active control condition. Analysis of the amplitude of the P300 ERP component evoked by the Self- or Target-names revealed no difference between the psychedelics users and nonusers. However, psychedelic users exhibited increased P300 amplitude during perception of Other-names. In addition, in comparison to nonusers, psychedelics users exhibited a smaller increase in P300 amplitude when processing the task-relevant Target-names (in relation to both Self- and Other-names). Therefore, our data suggests that regular naturalistic use of psychedelics may not be related to long-term changes in the representation of self, but it might potentially affect the allocation of attentional resources to task-relevant stimuli.

The Global Psychedelic Survey: Consumer characteristics, patterns of use, and access in primarily anglophone regions around the world

OBJECTIVES

Despite advancements in policies governing psychedelic substances globally, our understanding of real-world psychedelic use and its variations across international jurisdictions remains limited. We implemented the Global Psychedelic Survey (GPS) to capture information about psychedelic consumer characteristics, access, and usage patterns around the world.

METHODS

The GPS was administered online in Spring 2023 to English-speaking adults (≥21 years) who use(d) psychedelics. We categorized survey responses into major catchment regions (Canada/US, Europe/UK, Australia/NZ, All Other). We used descriptive and bivariable statistics to characterize consumers' socio-demographic characteristics, psychedelic access sources, and usage patterns. We examined regional differences in psychedelic use patterns using multinomial logistic regression.

RESULTS

We analyzed 6379 responses from 85 countries including Canada/US (n = 4434), Europe/UK (n = 771), Australia/NZ (n = 864), and Other (n = 310). Psilocybin, LSD, and MDMA were the most used psychedelics and personal growth was the most common use motive across all catchments. There were significant regional differences in psychedelic use patterns, including types of psychedelics used (e.g., less ibogaine use in Europe/UK and Australia/NZ relative to Canada/US), frequency of use (e.g., lower frequency use in Australia/NZ relative to Canada/US), motivations for use (e.g., less therapeutic use in Europe/UK and Other relative to Canada/US), and types of dosing regimens (e.g., more "micro"-dosing in Canada/US).

DISCUSSION

In this large sample of adult psychedelic consumers from regions around the world, infrequent psychedelic use centered around life enhancement was common. Respondents indicated preference for legal access via quality-controlled sources. Jurisdictional differences in access and usage patterns likely reflect region-specific regulations and traditional practices. Further research should explore opportunities to increase representation of non-White respondents in psychedelic research via translation of studies into several languages and incorporation of culturally reflective, community-based study development.

A framework for assessment of adverse events occurring in psychedelic-assisted therapies

OBJECTIVE

Despite considerable research examining the efficacy of psychedelic-assisted therapies (PATs) for treating psychiatric disorders, assessment of adverse events (AEs) in PAT research has lagged. Current AE reporting standards in PAT trials are poorly calibrated to features of PAT that distinguish it from other treatments, leaving many potential AEs unassessed.

METHODS

A multidisciplinary working group of experts involved in PAT pooled formally and informally documented AEs observed through research experience and published literature. This information was integrated with (a) current standards and practices for AE reporting in pharmacotherapy and psychotherapy trials and (b) published findings documenting post-acute dosing impacts of psychedelics on subjective states, meaning, and psychosocial health variables, to produce a set of AE constructs important to evaluate in PAT as well as recommended methods and time frames for their assessment and monitoring. Correspondence between identified potential AEs and current standards for AE assessment was examined, including the extent of coverage of identified AE constructs by 25 existing measures used in relevant research.

RESULTS

Fifty-four potential AE terms warranting systematized assessment in PAT were identified, defined, and categorized. Existing measures demonstrated substantial gaps in their coverage of identified AE constructs. Recommendations were developed for how to assess PAT AEs (including patient, clinician, and informant reports), and when to assess over preparation, dosing session, integration, and follow-up. Application of this framework is demonstrated in a preliminary assessment protocol (available in the supplement).

CONCLUSIONS

This assessment framework addresses the need to capture post-acute dosing AEs in PAT, accounting for its pharmacotherapy and psychotherapy components, as well as documented impacts of psychedelics on worldviews and spirituality.

Tripping into the unknown: Exploring the experiences of first-time LSD users through global drug survey insights

BACKGROUND

The recreational use of LSD, a synthetic psychedelic drug, has surged in recent years, coinciding with a renewed research focus on its potential psychotherapeutic properties.

AIM

This study aims to describe the experiences and perceptions of individuals engaging in LSD use for the first time, derived from a large international sample.

METHODS

This study utilised 2018 Global Drug Survey data collected from 6 November 2017 to 10 January 2018. Participants who initiated LSD use in the preceding 12 months answered questions on their experiences, social settings, harm-reduction behaviours, and demographics. Descriptive statistics were employed, and characteristics of those seeking emergency medical treatment (EMT) and those not planning further LSD use were compared with other respondents.

RESULTS

Among 3340 respondents who used LSD in the past year, their first-time experiences generally exceeded expectations, with 97.7% expressing excitement. Adverse and unwanted side effects were rarely reported, and only 17 individuals needed EMT. Feelings of fear were reported by most (64.1%), but only very mildly and not enough to put them off from wanting to use LSD again.

DISCUSSION

Although the occurrence of unwanted side effects seems low and the LSD experience is generally pleasurable, vigilance amid the rising illicit use of LSD through harm-reduction education is still important in preventing possible risks.

Psychedelic-assisted psychotherapy: where is the psychotherapy research?

RATIONALE

Psychedelic-assisted psychotherapy (PAP) has emerged as a potential treatment for a variety of mental health conditions, including substance use disorders and depression. Current models of PAP emphasize the importance of psychotherapeutic support before, during, and after ingestion of a psychedelic to maximize safety and clinical benefit. Despite this ubiquitous assumption, there has been surprisingly little empirical investigation of the "psychotherapy" in PAP, leaving critical questions about the necessary and sufficient components of PAP unanswered.

OBJECTIVES

As clinical trials for psychedelic compounds continue the transition from safety- and feasibility-testing to evaluating efficacy, the role of the accompanying psychotherapy must be better understood to enhance scientific understanding of the mechanisms underlying therapeutic change, optimize clinical outcomes, and inform cost-effectiveness.

RESULTS

The present paper first reviews the current status of psychotherapy in the PAP literature, starting with recent debates regarding "psychotherapy" versus "psychological support" and then overviewing published clinical trial psychotherapy models and putative models informed by theory. We then delineate lessons that PAP researchers can leverage from traditional psychotherapy research regarding standardizing treatments (e.g., publish treatment manuals, establish eligibility criteria for providers), identifying mechanisms of change (e.g., measure established mechanisms in psychotherapy), and optimizing clinical trial designs (e.g., consider dismantling studies, comparative efficacy trials, and cross-lagged panel designs). Throughout this review, the need for increased research into the psychotherapeutic components of treatment in PAP is underscored.

CONCLUSIONS

PAP is a distinct, integrative, and transdisciplinary intervention. Future research designs should consider transdisciplinary research methodologies to identify best practices and inform federal guidelines for PAP administration.

The cyclical revival of psychedelics in psychiatric treatment

There is an increasing demand for effective treatments for depression, particularly for individuals grappling with treatment-resistant depression. Over recent years, a surge of interest has focused on exploring the safety and efficacy of psilocybin as a potential treatment for depression. However, preliminary findings from phase 2 studies have been inconclusive, prompting critical examination of issues such as maintaining blinding and the role of adjunctive psychotherapy. The maintenance of double-blinding and the role of adjunctive psychotherapy introduce biases that complicate the attainment of conclusive results in clinical research. Examining historical data reveals a recurrent pattern linked to the use of psychoactive substances, which starts with an excess of optimism and ends with general addictive behaviors and a heightened risk of serious public health problems. Considering these findings, a cautious and measured approach is imperative, given that the efficacy and safety of psilocybin treatment have yet to be unequivocally established. The potential for excessive optimism among researchers is a notable concern, as unwarranted enthusiasm may inadvertently facilitate the widespread adoption of this treatment without sufficient empirical support. In navigating the complexities of depression treatment, it is necessary to strike a balance between innovation and prudence to ensure evidence-based advancement of therapeutic approaches.

Current Perspectives on the Clinical Research and Medicalization of Psychedelic Drugs for Addiction Treatments: Safety, Efficacy, Limitations and Challenges

Mental health disorders and substance use disorders (SUDs) in particular, contribute greatly to the global burden of disease. Psychedelics, including entactogens and dissociative substances, are currently being explored for the treatment of SUDs, yet with less empirical clinical evidence than for other mental health disorders, such as depression or post-traumatic stress disorder (PTSD). In this narrative review, we discuss the current clinical research evidence, therapeutic potential and safety of psilocybin, lysergic acid diethylamide (LSD), ketamine, 3,4-methylenedioxymethamphetamine (MDMA) and ibogaine, particularly in the context of the SUD treatment. Our aim was to provide a balanced overview of the current research and findings on potential benefits and harms of psychedelics in clinical settings for SUD treatment. We highlight the need for more clinical research in this particular treatment area and point out some limitations and challenges to be addressed in future research.

Psychedelic public health: State of the field and implications for equity

BACKGROUND

Psychedelic Public Health is an emerging discipline uniting the practices of public health with the potential benefits of psychedelics to reduce harm and promote health, wellness, and equity at community and population levels. Little is known regarding the current state of psychedelic public health despite rising psychedelic usage, evidence of its health efficacy, opening policy environments, and concerns regarding equity and potential harms.

METHODS

To characterize the current state of psychedelic public health, this survey reviewed relevant webpages from 228 universities housing accredited Schools and Programs in Public Health (SPPHs) and 59 Psychedelic Research Centers (PRCs) in the US and globally. The scan corresponded to the Prisma 2020 checklist, identifying URLs through keyword searches by Beautiful Soup python package and Google search engine web application. Measures were coded through webpage text analysis.

FINDINGS

Fewer than 10% (9.6%) of SPPHs engaged with psychedelics (2.6% substantially), while half (52.6%) of universities engaged (28.1% substantially). Among PRCs, only 10% indicated a collaboration with SPPHs, and fewer than 3% of PRC personnel held public health degrees. PRCs were preponderantly affiliated with medical schools. Although Indigeneity significantly contributes to Western therapeutic psychedelic protocols, only approximately one-quarter of active universities, SPPHs, or PRCs visibly addressed Indigeneity and only one PRC included Indigenous leadership. 92% of PRCs were led or co-led by people characterized as White-European and 88% by men. Only 20-43% of SPPHs, universities, and PRCs visibly addressed social determinants of health.

CONCLUSIONS

Public health schools, which train, study, and advise the future of public health, showed limited involvement in the growing psychedelic field, signifying a gap in psychedelic science and practice. The absence of public health's population-level approaches signifies a missed opportunity to maximize benefits and protect against potential harms of psychedelics at community and population levels.

A taxonomy of regulatory and policy matters relevant to psychedelic-assisted therapy in Australia

OBJECTIVES

The Australian government recently rescheduled psilocybin and 3,4-methylenedioxymethamphetamine for limited clinical uses. This change has raised various regulatory concerns and challenges for the field of psychedelic-assisted therapy. To provide clarity, we aimed to comprehensively catalogue the matters relating to psychedelic-assisted therapy that are or could be regulated.

METHODS

We conducted a desktop review of the literature and current regulatory sources, semi-structured interviews with professionals who had expertise in fields relating to psychedelic-assisted therapy and a framework analysis to generate a taxonomy of relevant regulatory matters. In relation to each matter, we further identified what type of regulation (if any) currently applies to that matter, any uncertainty as to how the matter should be addressed in clinical practice in the context of current regulation and whether there are conflicting views as to how the matter could or should be further regulated.

RESULTS

The taxonomy is structured into six main regulatory domains, three of which have a substantial proportion of matters with uncertainty or conflicting views: Service Establishment, Practitioner, and Treatment Delivery. Key examples of such matters include the location of services and facilities required, which professionals are eligible to become psychedelic therapists, and with what qualifications and experience. Matters in the remaining three domains, Patient Evaluation, Drug Supply and Service Oversight, appear by comparison relatively settled, with regulation either well-established or thought unnecessary.

CONCLUSIONS

The taxonomy provides a roadmap for health services establishing and implementing a psychedelic-assisted therapy program, or for government and other policymakers when determining areas that may require further regulation.

Cognitive functioning associated with acute and subacute effects of classic psychedelics and MDMA - a systematic review and meta-analysis

Classic psychedelics and MDMA have a colorful history of recreational use, and both have recently been re-evaluated as tools for the treatment of psychiatric disorders. Several studies have been carried out to assess potential long-term effects of a regular use on cognition, delivering distinct results for psychedelics and MDMA. However, to date knowledge is scarce on cognitive performance during acute effects of those substances. In this systematic review and meta-analysis, we investigate how cognitive functioning is affected by psychedelics and MDMA during the acute drug effects and the sub-acute ("afterglow") window. Our quantitative analyses suggest that acute cognitive performance is differentially affected by psychedelics when compared to MDMA: psychedelics impair attention and executive function, whereas MDMA primarily affects memory, leaving executive functions and attention unaffected. Our qualitative analyses reveal that executive functioning and creativity may be increased during a window of at least 24 h after the acute effects of psychedelics have subsided, whereas no such results have been observed for MDMA. Our findings may contribute to inform recommendations on harm reduction for recreational settings and to help fostering differential approaches for the use of psychedelics and MDMA within a therapeutic framework.

Psychedelics in developmental stuttering to modulate brain functioning: a new therapeutic perspective?

Developmental stuttering (DS) is a neurodevelopmental speech-motor disorder characterized by symptoms such as blocks, repetitions, and prolongations. Persistent DS often has a significant negative impact on quality of life, and interventions for it have limited efficacy. Herein, we briefly review existing research on the neurophysiological underpinnings of DS -specifically, brain metabolic and default mode/social-cognitive networks (DMN/SCN) anomalies- arguing that psychedelic compounds might be considered and investigated (e.g., in randomized clinical trials) for treatment of DS. The neural background of DS is likely to be heterogeneous, and some contribution from genetically determinants of metabolic deficiencies in the basal ganglia and speech-motor cortical regions are thought to play a role in appearance of DS symptoms, which possibly results in a cascade of events contributing to impairments in speech-motor execution. In persistent DS, the difficulties of speech are often linked to a series of associated aspects such as social anxiety and social avoidance. In this context, the SCN and DMN (also influencing a series of fronto-parietal, somato-motor, and attentional networks) may have a role in worsening dysfluencies. Interestingly, brain metabolism and SCN/DMN connectivity can be modified by psychedelics, which have been shown to improve clinical evidence of some psychiatric conditions (e.g., depression, post-traumatic stress disorder, etc.) associated with psychological constructs such as rumination and social anxiety, which also tend to be present in persistent DS. To date, while there have been no controlled trials on the effects of psychedelics in DS, anecdotal evidence suggests that these agents may have beneficial effects on stuttering and its associated characteristics. We suggest that psychedelics warrant investigation in DS.

Mechanisms of therapeutic change after psychedelic treatment in OCD

Novel treatments are required for the 30-50% of individuals with obsessive-compulsive disorder (OCD) who remain resistant to first-line pharmacological and psychotherapeutic treatments. Recent pilot data suggest benefit from psilocybin-assisted psychotherapy (PAP) and from imagery rescripting (ImRs). We explore psychological mechanisms of change underpinning both interventions that appear to allow for reprocessing of negative emotions and core beliefs associated with past aversive events. A next critical step in PAP is the development of psychotherapeutic frameworks grounded in theory. We propose that basing PAP on an ImRs framework may provide synergistic benefits in symptom reduction, modification of core beliefs, and value-based living.

Attitudes of European psychiatrists on psychedelics: a qualitative study

Introduction and aim

It is important to understand how mental health practitioners view recent findings on psychedelic-assisted psychotherapy (PAP) as there is potential this treatment may be incorporated into clinical practice. The aim of our study was to explore how psychiatrists who are not involved in psychedelic research and who are located in the European region perceive psychedelics and PAP.

Methods

We conducted online semi-structured interviews with 12 psychiatry specialists and psychiatry trainees from 8 European countries. Data were analyzed using a general inductive approach informed by codebook thematic analysis.

Results

Based on the interviews, we developed four main themes and 14 sub-themes, including (1) Psychedelics hold potential, (2) Psychedelics are dangerous, (3) Future of psychedelics is uncertain, and (4) Psychiatry is ambivalent toward psychedelics.

Discussion

Our respondents-psychiatrists acknowledged the potential of PAP but remained cautious and did not yet perceive its evidence base as robust enough. Education on psychedelics is lacking in medical and psychiatric training and should be improved to facilitate the involvement of mental health experts in decision-making on PAP.

Stutterers' experiences on classic psychedelics: A preliminary self-report study

Stuttering poses challenges to social, occupational, and educational aspects of life. Traditional behavioral therapies can be helpful but effects are often limited. Pharmaceutical treatments have been explored but there are no FDA-approved treatments for stuttering. Interest has grown in the potential use of classic psychedelics, including psilocybin and LSD, which have shown effectiveness in treating disorders with similar symptoms (e.g., anxiety, depression, PTSD). The potential effects of psychedelics on stuttering have not been explored. We conducted a preliminary investigation of self-identified stutterers who report their experiences taking classic psychedelics on the online messaging forum, Reddit. We qualitatively analyzed 114 publicly available posts, extracting meaningful units and assigning descriptor codes inductively. We then deductively organized responses into an established framework of psychedelics which includes behavioral, emotional, cognitive, belief-based, and social effects. These effects were subsequently grouped under organizing themes (positive, negative, neutral). Descriptive statistics revealed that the majority of users (74.0%) reported positive overall short-term effects particularly related to behavioral and emotional change (e.g., reduced stuttering and anxiety), but negative (9.6%), mixed (positive and negative; 4.8%), and neutral overall experiences (11.6%) were also reported. The results support the possibility that psychedelics may impact stuttering, but caution must be applied in their interpretation given the entirely uncontrolled research setting and potential adverse health effects of psychedelics as reported elsewhere. While these results do not encourage the use of psychedelics by stutterers, they suggest that future work could examine the impact of psychedelics on stuttering under supervised and in clinically controlled settings.

Personality traits explain the relationship between psychedelic use and less depression in a comparative study

Interest in psychedelics is increasing due to the potential for improved mental health and quality of life. However, adverse effects on mental health are still a concern. Personality traits have been suggested to both influence the psychedelic experience and mental health, and even be changed by psychedelic use. The present study describes for the first time a national sample of Swedish psychedelic users (n = 400) compared to a sex and age-matched control-group of non-users (n = 400) regarding mental health variables (depression, insomnia, problematic alcohol and drug use, and dissociation) and personality (Big Five). Data was collected in an online survey including individuals from 16 years of age who had at least one psychedelic experience. The main results reported psychedelic users as less depressed (Patient Health Questionnaire-9; PHQ-9) (d = - 0.29) and having more use of drugs (Drug Use Disorders Identification Test; DUDIT) (d = 1.27). In the Big Five personality traits, openness differed notably (d = 1.72), and the between-group effects in PHQ-9 were explained by lower neuroticism. Our findings reveal that psychedelic users report less depression and higher drug use, and this is partly due to personality traits. These results have implications on how we view psychedelic users and the use of psychedelic drugs.

Safety and risk assessment of psychedelic psychotherapy: A meta-analysis and systematic review

Psychotherapies assisted by psychedelic substances have shown promising results in the treatment of psychiatric disorders. The aim of this systematic review and meta-analysis was to evaluate safety data in human subjects. We carried out a search on MEDLINE, Embase and PsycINFO databases between 2000 and 2022. Standardized mean differences between different dose ranges and between acute and subacute phases were calculated for cardiovascular data after psychedelic administration. Risk differences were calculated for serious adverse events and common side effects. Thirty studies were included in this meta-analysis. There were only nine serious adverse events for over 1000 administrations of psychedelic substances (one during the acute phase and 8 during the post-acute phase). There were no suicide attempts during the acute phase and 3 participants engaged in self-harm during the post-acute phase. There was an increased risk for elevated heart rate, systolic and diastolic blood pressure for all dose range categories, as well as an increased risk of nausea during the acute phase. Other common side effects included headaches, anxiety, and decreased concentration or appetite. This meta-analysis demonstrates that psychedelics are well-tolerated, with a low risk of emerging serious adverse events in a controlled setting with appropriate inclusion criteria.

Trends in hallucinogen-associated emergency department visits and hospitalizations in California, USA, from 2016 to 2022

BACKGROUND AND AIMS

Hallucinogens encompass a diverse range of compounds of increasing scientific and public interest. Risks associated with hallucinogen use are under-researched and poorly understood. We aimed to compare the trends in hallucinogen-associated health-care use with alcohol- and cannabis-associated health-care use.

DESIGN, SETTING AND CASES

We conducted an ecological study with publicly available data on International Classification of Diseases, 10th Revision (ICD-10) diagnosis codes associated with emergency department (ED) visits and hospitalizations from the California Department of Healthcare Access and Information (HCAI). HCAI includes primary and secondary ICD-10 codes reported with ED or hospital discharge from every non-federal health-care facility licensed in California, United States, from 2016 to 2022.

MEASUREMENTS

ICD-10 codes were classified as hallucinogen-, cannabis- or alcohol-associated if they were from the corresponding category in the ICD-10 block 'mental and behavioral disorders due to psychoactive substance use'.

FINDINGS

Observed hallucinogen-associated ED visits increased by 54% between 2016 and 2022, from 2260 visits to 3476 visits, compared with a 20% decrease in alcohol-associated ED visits and a 15% increase in cannabis-associated ED visits. The observed hallucinogen-associated hospitalizations increased by 55% during the same period, from 2556 to 3965 hospitalizations, compared with a 1% increase in alcohol-associated hospitalizations and a 1% increase in cannabis-associated hospitalizations. This rise in hallucinogenic ED visits was significantly different from the trend in cannabis-associated (P < 0.001) and alcohol-associated (P = 0.005) ED visits. The hallucinogen-associated hospitalizations trend also significantly differed when compared with cannabis- (P < 0.001) and alcohol-associated (P < 0.001) hospitalizations.

CONCLUSIONS

Hallucinogen-associated emergency department visits and hospitalizations in California, USA, showed a large relative but small absolute increase between 2016 and 2022.

The effect of psychedelics on the level of brain-derived neurotrophic factor: A systematic review and meta-analysis

BACKGROUND

Recent interest in the potential therapeutic effects of psychedelics has led to investigations into their influence on molecular signaling pathways within the brain.

AIMS

Integrated review and analysis of different studies in this field.

METHODS

A systematic search was conducted across international databases including Embase, Scopus, Web of Science, and PubMed from inception to 9 July 2023. Eligibility criteria encompassed published and peer-reviewed studies evaluating changes in brain-derived neurotrophic factor (BDNF) levels after psychedelic consumption.

OUTCOMES

A total of nine studies were included in our study. The meta-analysis demonstrated significantly higher BDNF levels in psychedelic consumers compared to healthy controls, with a pooled standardized mean difference of 0.26 (95% CI: 0.10-0.42, I2 = 38.51%, p < 0.001). Leave-one-out analysis indicated robustness in results upon removal of individual psychedelics. No significant publication bias was observed. The results highlight the potential influence of psychedelics on neuroplasticity by altering BDNF levels.

CONCLUSIONS

More precisely, the documented rise in BDNF levels indicates a neurobiological mechanism by which psychedelics could enhance synaptic plasticity and foster the growth of neurons. Given the limited data available on this topic, the conclusions remain uncertain. Consequently, we highly recommend additional research with more extensive sample sizes to yield more reliable evidence in this field.

Longitudinal associations between psychedelic use and psychotic symptoms in the United States and the United Kingdom

It has long been speculated that psychedelic use could provoke the onset of psychosis, but there is little evidence to support this conjecture. Using a longitudinal research design with samples representative of the US and UK adult populations with regard to sex, age, and ethnicity (n = 9732), we investigated associations between psychedelic use and change in the number of psychotic symptoms during the two-month study period. In covariate-adjusted regression models, psychedelic use during the study period was not associated with a change in the number of psychotic symptoms unless it interacted with a personal or family history of bipolar disorder, in which case the number of symptoms increased, or with a personal (but not family) history of psychotic disorders, in which case the number of symptoms decreased. Taken together, these findings indicate that psychedelic use may affect psychotic symptoms in individuals with a personal or family history of certain disorders characterized by psychotic symptomatology.

Strong Bipartisan Support for Controlled Psilocybin Use as Treatment or Enhancement in a Representative Sample of US Americans: Need for Caution in Public Policy Persists

The psychedelic psilocybin has shown promise both as treatment for psychiatric conditions and as a means of improving well-being in healthy individuals. In some jurisdictions (e.g., Oregon, USA), psilocybin use for both purposes is or will soon be allowed and yet, public attitudes toward this shift are understudied. We asked a nationally representative sample of 795 US Americans to evaluate the moral status of psilocybin use in an appropriately licensed setting for either treatment of a psychiatric condition or well-being enhancement. Showing strong bipartisan support, participants rated the individual's decision as morally positive in both contexts. These results can inform effective policy-making decisions around supervised psilocybin use, given robust public attitudes as elicited in the context of an innovative regulatory model. We did not explore attitudes to psilocybin use in unsupervised or non-licensed community or social settings.

Psilocybin enhances insightfulness in meditation: a perspective on the global topology of brain imaging during meditation

In this study, for the first time, we explored a dataset of functional magnetic resonance images collected during focused attention and open monitoring meditation before and after a five-day psilocybin-assisted meditation retreat using a recently established approach, based on the Mapper algorithm from topological data analysis. After generating subject-specific maps for two groups (psilocybin vs. placebo, 18 subjects/group) of experienced meditators, organizational principles were uncovered using graph topological tools, including the optimal transport (OT) distance, a geometrically rich measure of similarity between brain activity patterns. This revealed characteristics of the topology (i.e. shape) in space (i.e. abstract space of voxels) and time dimension of whole-brain activity patterns during different styles of meditation and psilocybin-induced alterations. Most interestingly, we found that (psilocybin-induced) positive derealization, which fosters insightfulness specifically when accompanied by enhanced open-monitoring meditation, was linked to the OT distance between open-monitoring and resting state. Our findings suggest that enhanced meta-awareness through meditation practice in experienced meditators combined with potential psilocybin-induced positive alterations in perception mediate insightfulness. Together, these findings provide a novel perspective on meditation and psychedelics that may reveal potential novel brain markers for positive synergistic effects between mindfulness practices and psilocybin.

Psychedelic-assisted therapy for people with gambling disorder?

Gambling disorder is a severe mental health and behavioural problem with harmful consequences, including financial, relationship and mental health problems. The present paper initiates discussion on the use of psychedelics combined with psychotherapeutic support as a potential treatment option for people living with a gambling disorder. Recent studies have shown promising results using psychedelic-assisted therapy (PAT) to treat anxiety, depression, post-traumatic stress disorder, and various substance use disorders. Considering the similarities in the underlying psychosocial and neurobiological mechanisms of gambling disorder and other addictive disorders, the authors suggest that psychedelic-assisted therapy could be effective in treating gambling disorder. The paper also underscores the need for further research into the viability and effectiveness of psychedelic-assisted therapy for gambling disorder.

Scoping Review: The Role of Psychedelics in the Management of Chronic Pain

Introduction

Amid a lack of effective chronic pain treatments, psychedelics have gained attention as a potential solution, although their Schedule 1 classification poses challenges. Psychedelics, such as lysergic acid diethylamide (LSD) and psilocybin, have gained popularity as alternatives and adjuncts for chronic pain treatment. Studies suggest that they may modulate pain processing through agonism primarily at the serotonin receptor, 5-HT2A. One of the first of its nature, we present an artificial intelligence (AI)-powered scoping review primarily focusing on evaluating psychedelics for chronic pain conditions such as cluster headache, phantom limb pain, and fibromyalgia.

Methods

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, we used an AI-powered comprehensive search strategy utilizing the ChatGPT4.0 Bing chat to search Medline, Embase, Cochrane, and Google Scholar for articles addressing chronic pain. The query was performed on June 1, 2023, focusing on psychedelics for chronic, non-cancer pain including headache disorders. Inclusion criteria were English-only, peer-reviewed articles involving human participants >18 years, focusing on chronic pain conditions (eg, phantom limb pain and cluster headache), using LSD, 2.5-dimethoxy-4-bromophenethylamine (2C-B), N, N-dimethyltryptamine (DMT), psilocybin, or mescaline. Exclusion criteria were reviews, editorials, and opinion articles and studies focusing on tetrahydrocannabinol/cannabis and/or ketamine.

Results

A total of 186 unique database entries were retrieved, of which nine studies were included in the scoping review. These included four case reports/series, an open-label study, a cohort study, two online surveys, and a randomized, double-blind, placebo-controlled trial. They comprised three studies addressing phantom limb pain, four addressing cluster headaches, and two addressing fibromyalgia, spinal cord injury, complex regional pain syndrome, and lumbar radiculopathy.

Conclusion

Psychedelics may have potential in alleviating pain symptoms secondary to a multitude of chronic pain conditions. However, further randomized, double-blind, placebo-controlled trials are needed to further explore and evaluate the role of psychedelics in chronic, non-cancer pain.

Pharmaco-toxicological effects of the novel tryptamine hallucinogen 5-MeO-MiPT on motor, sensorimotor, physiological, and cardiorespiratory parameters in mice-from a human poisoning case to the preclinical evidence

RATIONALE

The 5-methoxy-N-methyl-N-isopropyltryptamine (5-MeO-MiPT, known online as "Moxy") is a new psychedelic tryptamine first identified on Italian national territory in 2014. Its hallucinogen effects are broadly well-known; however, only few information is available regarding its pharmaco-toxicological effects.

OBJECTIVES

Following the seizure of this new psychoactive substances by the Arm of Carabinieri and the occurrence of a human intoxication case, in the current study we had the aim to characterize the in vivo acute effects of systemic administration of 5-MeO-MiPT (0.01-30 mg/kg i.p.) on sensorimotor (visual, acoustic, and overall tactile) responses, thermoregulation, and stimulated motor activity (drag and accelerod test) in CD-1 male mice. We also evaluated variation on sensory gating (PPI, prepulse inhibition; 0.01-10 mg/kg i.p.) and on cardiorespiratory parameters (MouseOx and BP-2000; 30 mg/kg i.p.). Lastly, we investigated the in silico ADMET (absorption, distribution, metabolism, excretion, toxicity) profile of 5-MeO-MiPT compared to 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT) and N,N-dimethyltryptamine (DMT).

RESULTS

This study demonstrates that 5-MeO-MiPT dose-dependently inhibits sensorimotor and PPI responses and, at high doses, induces impairment of the stimulated motor activity and cardiorespiratory changes in mice. In silico prediction shows that the 5-MeO-MiPT toxicokinetic profile shares similarities with 5-MeO-DIPT and DMT and highlights a cytochrome risk associated with this compound.

CONCLUSIONS

Consumption of 5-MeO-MiPT can affect the ability to perform activities and pose a risk to human health status, as the correspondence between the effects induced in mice and the symptoms occurred in the intoxication case suggests. However, our findings suggest that 5-MeO-MiPT should not be excluded from research in the psychiatric therapy field.

Psychiatric risks for worsened mental health after psychedelic use

BACKGROUND

Resurgent psychedelic research has largely supported the safety and efficacy of psychedelic therapy for the treatment of various psychiatric disorders. As psychedelic use and therapy increase in prevalence, so does the importance of understanding associated risks. Cases of prolonged negative psychological responses to psychedelic therapy seem to be rare; however, studies are limited by biases and small sample sizes. The current analytical approach was motivated by the question of whether rare but significant adverse effects have been under-sampled in psychedelic research studies.

METHODS

A "bottom margin analysis" approach was taken to focus on negative responders to psychedelic use in a pool of naturalistic, observational prospective studies (N = 807). We define "negative response" by a clinically meaningful decline in a generic index of mental health, that is, one standard error from the mean decrease in psychological well-being 4 weeks post-psychedelic use (vs pre-use baseline). We then assessed whether a history of diagnosed mental illness can predict negative responses.

RESULTS

We find that 16% of the cohort falls into the "negative responder" subset. Parsing the sample by self-reported history of psychiatric diagnoses, results revealed a disproportionate prevalence of negative responses among those reporting a prior personality disorder diagnosis (31%). One multivariate regression model indicated a greater than four-fold elevated risk of adverse psychological responses to psychedelics in the personality disorder subsample (b = 1.425, p < 0.05).

CONCLUSION

We infer that the presence of a personality disorder may represent an elevated risk for psychedelic use and hypothesize that the importance of psychological support and good therapeutic alliance may be increased in this population.

Psychedelic Therapy: A Primer for Primary Care Clinicians-Lysergic Acid Diethylamide (LSD)

BACKGROUND

Lysergic acid diethylamide (LSD) is a hallucinogenic agent. In the mid-20th century, it was used to augment psychoanalysis and to treat alcohol use disorder. However, LSD was banned in 1970 in part because of concerns that it could bring about or exacerbate mental illness. Its therapeutic potential remains incompletely understood.

AREAS OF UNCERTAINTY

While uncontrolled recreational use of LSD can, in rare instances, lead to long-term psychosis, adverse events in clinical trials of LSD, such as anxiety, headache, and nausea, have almost always been mild and transient. Serious adverse events, such as intense panic, suicidal ideation, and psychosis, were reported in either none or very few of the participants. However, patient selection criteria, optimal dosing strategy, and appropriate clinical follow-up guidelines remain to be established.

THERAPEUTIC ADVANCES

Preliminary data suggest that LSD may be effective for the management of alcohol use disorder, anxiety, and depression. In trials of LSD for treating anxiety and depression associated with life-threatening illnesses, 77% of participants demonstrate durable relief at 1 year post-treatment. Top-line data from a large-scale phase IIb trial (n = 198) indicate that 50% of participants experience remission from generalized anxiety disorder after a single 100 μg dose of LSD. According to a meta-analysis of RCTs on LSD from the mid-20th century, single-dose regimens of LSD significantly improve alcohol use disorder (P < 0.0003) with an odds ratio (OR) of 1.96.

LIMITATIONS

Only one large-scale clinical trial (>50 participants) has been conducted on LSD in the contemporary era of psychedelic research. Further studies with large sample sizes are needed to explore potential clinical applications.

CONCLUSIONS

Preliminary data suggest that LSD may be one of the most potent treatments for anxiety in patients both with and without a life-threatening illness. LSD may also be beneficial for treating depression and substance use disorders.

Psychedelics for acquired brain injury: a review of molecular mechanisms and therapeutic potential

Acquired brain injury (ABI), such as traumatic brain injury and stroke, is a leading cause of disability worldwide, resulting in debilitating acute and chronic symptoms, as well as an increased risk of developing neurological and neurodegenerative disorders. These symptoms can stem from various neurophysiological insults, including neuroinflammation, oxidative stress, imbalances in neurotransmission, and impaired neuroplasticity. Despite advancements in medical technology and treatment interventions, managing ABI remains a significant challenge. Emerging evidence suggests that psychedelics may rapidly improve neurobehavioral outcomes in patients with various disorders that share physiological similarities with ABI. However, research specifically focussed on psychedelics for ABI is limited. This narrative literature review explores the neurochemical properties of psychedelics as a therapeutic intervention for ABI, with a focus on serotonin receptors, sigma-1 receptors, and neurotrophic signalling associated with neuroprotection, neuroplasticity, and neuroinflammation. The promotion of neuronal growth, cell survival, and anti-inflammatory properties exhibited by psychedelics strongly supports their potential benefit in managing ABI. Further research and translational efforts are required to elucidate their therapeutic mechanisms of action and to evaluate their effectiveness in treating the acute and chronic phases of ABI.

Psychedelic Therapy: A Primer for Primary Care Clinicians-The Strengths, Weaknesses, Opportunities, and Threats of Psychedelic Therapeutics

The reviews in this special edition have presented a primer on the state of the literature for 7 different psychedelic compounds and their plausible roles in medicine. In a common format underscoring strengths, weakness, opportunities, and threats (SWOT), this article addresses how psychedelic compounds fit into the broader health care landscape for indicated conditions. Historically, psychiatric pathologies have been treated with small-molecule compounds that have limited effect sizes and carry a variety of adverse effect profiles. Psychedelic medicines offer the opportunity to provide more potent and rapidly acting treatments. It is crucial to note that this is an emerging field of medicine, and only one of these compounds (esketamine) is currently Food and Drug Administration-approved for depression. The other compounds discussed are investigational, and this discussion is both imaginative and prospective in nature.

Psychedelic Microdosing among Young Adults from Southern California

Despite common depictions in the media, there is little scientific evidence on microdosing psychedelic drugs. We assessed awareness, prevalence, and dosing practices of microdosing psychedelic drugs among young adults 18-22 years old from Southern California (2018-2019). We examined whether sociodemographic factors, personality traits, mental health, or other substance use behaviors were correlated with having ever microdosed. Among 2,396 participants, 293 (12%) had heard of microdosing and 74 (3%) ever microdosed. Among those who had heard of microdosing, 79% correctly defined microdosing as taking an amount of a psychedelic much lower than a standard dose, whereas 15% misperceived microdosing as a standard psychedelic dose. Psilocybin was the most common drug ever microdosed (70%), followed by lysergic acid diethylamide (LSD, 57%). Among those who ever microdosed, ~18% reported using psychoactive doses far higher than would be generally considered a microdose. White race, male/masculine gender identity, bisexual identity, past 6-month other drug use, greater attention deficit/hyperactivity disorder symptoms, mindfulness, and sensation-seeking were positively associated with having ever microdosed in multivariable models. Young adult microdosing merits further attention from scientific and public health professionals to help prevent misperceptions and potential adverse consequences as well as explore its potential therapeutic applications.

The changing outlook of psychedelic drugs: The importance of risk assessment and occupational exposure limits

Serotonergic psychedelics, such as lysergic acid diethylamide (LSD), psilocybin, dimethyltryptamine (DMT), and 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), are currently being investigated for the treatment of psychiatric disorders such as depression and anxiety. Clinical trials with psilocybin and LSD have shown improvement in emotional and psychological scores. Although these drugs are reported to be safe in a controlled environment (such as clinical trials), exposure to low doses of these drugs can result in psychedelic effects, and therefore, occupational safety is an important consideration to prevent adverse effects in the workplace from low daily exposure. This article will discuss the factors involved in the derivation of occupational exposure limits (OELs) and risk assessment of these psychedelic drugs. To support the OEL derivations of psychedelic drugs, information regarding their mechanism of action, adverse effect profiles, pharmacokinetics, clinical effects, and nonclinical toxicity were considered. Additionally, psilocybin and LSD, which are the most extensively researched psychedelic substances, are employed as illustrative examples in case studies. The OELs derived for psilocybin and for LSD are 0.05 and 0.002 μg/m3 , respectively, which indicates that these are highly hazardous compounds, and it is important to take into account suitable safety measures and risk-management strategies in order to minimize workplace exposure.

Set and setting predict psychopathology, wellbeing and meaningfulness of psychedelic experiences: a correlational study

BACKGROUND

In psychedelic therapy, the importance of set and setting is a fundamental but under-researched assumption. The aim of this study is to correlate variables of set (psychedelic use motivation) and setting (psychedelic use location and type of companion) with psychopathology, wellbeing and personality variables.

RESEARCH DESIGN AND METHODS

A sample of 1022 participants of the Spanish-speaking population was collected through an online survey. A novel instrument, the Psychedelic Use Scale (PUS), was developed to measure substance use variables of LSD, mescaline, psilocybin, DMT, 5-Meo-DMT, ketamine, Salvia divinorum, ibogaine and MDMA. Various personality, well-being and psychopathology instruments were implemented to measure outcome variables.

RESULTS

Growth motivations, natural settings and presence of significant others predicted less psychopathology, greater wellbeing and meaningfulness of psychedelic experiences, whereas problematic motivations predicted greater psychopathology, lower wellbeing and did not predict meaningfulness of psychedelic experiences.

CONCLUSIONS

Based on these results, we suggest experimental hypotheses for future clinical trials and longitudinal studies with potential clinical implications.

Longitudinal associations between psychedelic use and unusual visual experiences in the United States and the United Kingdom

BACKGROUND

Whereas findings from case reports and cross-sectional studies suggest that naturalistic psychedelic use may be associated with unusual visual experiences that occur after the acute pharmacological effects have subsided, such findings need to be replicated in longitudinal studies to better understand potential cause-and-effect relationships.

AIMS

To investigate longitudinal associations between naturalistic psychedelic use and unusual visual experiences.

METHODS

Using a longitudinal observational research design with samples representative of the US and UK adult populations with regard to sex, age, and ethnicity (N = 9732), we investigated the relationship between psychedelic use during the 2-month study period and changes in past-week unusual visual experiences.

RESULTS

The follow-up survey was completed by 79% of respondents (n = 7667), with 100 respondents reporting psychedelic use during the 2-month study period (1.3% of those who responded at follow-up). In covariate-adjusted regression models, the results showed that, as hypothesized, psychedelic use during the 2-month study period was associated with greater increases in unusual visual experiences. Notably, there was an interaction between lifetime psychedelic use and psychedelic use during the study period on unusual visual experiences such that those who used psychedelics for the first time reported greater increases in unusual visual experiences.

CONCLUSIONS

Psychedelic use may elicit unusual visual experiences that occur after the acute pharmacological effects have subsided, especially among those who have not used psychedelics previously. Future longitudinal studies are warranted to further elucidate these relationships.

Lysergic acid diethylamide stimulates cardiac human H2 histamine and cardiac human 5-HT4-serotonin receptors

Lysergic acid diethylamide (LSD) is an artificial hallucinogenic drug. Thus, we hypothesized that LSD might act 5-HT4 serotonin receptors and/or H2 histamine receptors. We studied isolated electrically stimulated left atrial preparations, spontaneously beating right atrial preparations, and spontaneously beating Langendorff-perfused hearts from transgenic mice with cardiomyocyte-specific overexpression of the human 5-HT4 receptor (5-HT4-TG) or of the H2-histamine receptor (H2-TG). For comparison, we used wild type littermate mice (WT). Finally, we measured isometric force of contraction in isolated electrically stimulated muscle strips from the human right atrium obtained from patients during bypass surgery. LSD (up to 10 µM) concentration dependently increased force of contraction and beating rate in left or right atrial preparations from 5-HT4-TG (n = 6, p < 0.05) in 5-HT4-TG atrial preparations. The inotropic and chronotropic effects of LSD were antagonized by 10 µM tropisetron in 5-HT4-TG. In contrast, LSD (10 µM) increased force of contraction and beating rate in left or right atrial preparations, from H2-TG. After pre-stimulation with cilostamide (1 µM), LSD (10 µM) increased force of contraction in human atrial preparations (n = 6, p < 0.05). The contractile effects of LSD in human atrial preparations could be antagonized by 10 µM cimetidine and 1 µM GR 125487. LSD leads to H2-histamine receptor and 5-HT4-receptor mediated cardiac effects in humans.

The Psychedelic Future of Post-Traumatic Stress Disorder Treatment

Post-traumatic stress disorder (PTSD) is a mental health condition that can occur following exposure to a traumatic experience. An estimated 12 million U.S. adults are presently affected by this disorder. Current treatments include psychological therapies (e.g., exposure-based interventions) and pharmacological treatments (e.g., selective serotonin reuptake inhibitors (SSRIs)). However, a significant proportion of patients receiving standard-of-care therapies for PTSD remain symptomatic, and new approaches for this and other trauma-related mental health conditions are greatly needed. Psychedelic compounds that alter cognition, perception, and mood are currently being examined for their efficacy in treating PTSD despite their current status as Drug Enforcement Administration (DEA)- scheduled substances. Initial clinical trials have demonstrated the potential value of psychedelicassisted therapy to treat PTSD and other psychiatric disorders. In this comprehensive review, we summarize the state of the science of PTSD clinical care, including current treatments and their shortcomings. We review clinical studies of psychedelic interventions to treat PTSD, trauma-related disorders, and common comorbidities. The classic psychedelics psilocybin, lysergic acid diethylamide (LSD), and N,N-dimethyltryptamine (DMT) and DMT-containing ayahuasca, as well as the entactogen 3,4-methylenedioxymethamphetamine (MDMA) and the dissociative anesthetic ketamine, are reviewed. For each drug, we present the history of use, psychological and somatic effects, pharmacology, and safety profile. The rationale and proposed mechanisms for use in treating PTSD and traumarelated disorders are discussed. This review concludes with an in-depth consideration of future directions for the psychiatric applications of psychedelics to maximize therapeutic benefit and minimize risk in individuals and communities impacted by trauma-related conditions.

Psilocybin and Eugenol Reduce Inflammation in Human 3D EpiIntestinal Tissue

Inflammation plays a pivotal role in the development and progression of inflammatory bowel disease (IBD), by contributing to tissue damage and exacerbating the immune response. The investigation of serotonin receptor 2A (5-HT2A) ligands and transient receptor potential (TRP) channel ligands is of significant interest due to their potential to modulate key inflammatory pathways, mitigate the pathological effects of inflammation, and offer new avenues for therapeutic interventions in IBD. This study investigates the anti-inflammatory effects of 5-HT2A ligands, including psilocybin, 4-AcO-DMT, and ketanserin, in combination with TRP channel ligands, including capsaicin, curcumin, and eugenol, on the inflammatory response induced by tumor necrosis factor (TNF)-α and interferon (IFN)-γ in human 3D EpiIntestinal tissue. Enzyme-linked immunosorbent assay was used to assess the expression of pro-inflammatory markers TNF-α, IFN-γ, IL-6, IL-8, MCP-1, and GM-CSF. Our results show that psilocybin, 4-AcO-DMT, and eugenol significantly reduce TNF-α and IFN-γ levels, while capsaicin and curcumin decrease these markers to a lesser extent. Psilocybin effectively lowers IL-6 and IL-8 levels, but curcumin, capsaicin, and 4-AcO-DMT have limited effects on these markers. In addition, psilocybin can significantly decrease MCP-1 and GM-CSF levels. While ketanserin lowers IL-6 and GM-CSF levels, there are no effects seen on TNF-α, IFN-γ, IL-8, or MCP-1. Although synergistic effects between 5-HT2A and TRP channel ligands are minimal in this study, the results provide further evidence of the anti-inflammatory effects of psilocybin and eugenol. Further research is needed to understand the mechanisms of action and the feasibility of using these compounds as anti-inflammatory therapies for conditions like IBD.

The possible place for psychedelics in pharmacotherapy of mental disorders

Since its emergence in the 1960s, the serotonergic theory of depression bore fruit in the discovery of a plethora of antidepressant drugs affecting the lives of millions of patients. While crucial in the history of drug development, recent studies undermine the effectiveness of currently used antidepressant drugs in comparison to placebo, emphasizing the long time it takes to initiate the therapeutic response and numerous adverse effects. Thus, the scope of contemporary pharmacological research shifts from drugs affecting the serotonin system to rapid-acting antidepressant drugs. The prototypical representative of the aforementioned class is ketamine, an NMDA receptor antagonist capable of alleviating the symptoms of depression shortly after the drug administration. This discovery led to a paradigm shift, focusing on amino-acidic neurotransmitters and growth factors. Alas, the drug is not perfect, as its therapeutic effect diminishes circa 2 weeks after administration. Furthermore, it is not devoid of some severe side effects. However, there seems to be another, more efficient, and safer way to target the glutamatergic system. Hallucinogenic agonists of the 5-HT2A receptor, commonly known as psychedelics, are nowadays being reconsidered in clinical practice, shedding their infamous 1970s stigma. More and more clinical studies prove their clinical efficacy and rapid onset after a single administration while bearing fewer side effects. This review focuses on the current state-of-the-art literature and most recent clinical studies concerning the use of psychedelic drugs in the treatment of mental disorders. Specifically, the antidepressant potential of LSD, psilocybin, DMT, and 5-MeO-DMT will be discussed, together with a brief summary of other possible applications.

Cardiovascular safety of psychedelic medicine: current status and future directions

Psychedelics are powerful psychoactive substances that alter perception and mood processes. Their effectiveness in the treatment of psychiatric diseases was known before their prohibition. An increasing number of recent studies, due to the indisputable resurgence of serotonergic hallucinogens, have shown their efficacy in alleviating depression, anxiety, substance abuse therapies, and existential distress treatment in patients facing life-threatening illness. Psychedelics are generally considered to be physiologically safe with low toxicity and low addictive potential. However, their agonism at serotonergic receptors should be considered in the context of possible serotonin-related cardiotoxicity (5-HT2A/2B and 5-HT4 receptors), influence on platelet aggregation (5-HT2A receptor), and their proarrhythmic potential. The use of psychedelics has also been associated with significant sympathomimetic effects in both experimental and clinical studies. Therefore, the present review aims to provide a critical discussion of the cardiovascular safety of psilocybin, d-lysergic acid diethylamide (LSD), N,N-dimethyltryptamine, ayahuasca, and mescaline, based on the results of experimental research and clinical trials in humans. Experimental studies provide inconsistent information on the potential cardiovascular effects and toxicity of psychedelics. Data from clinical trials point to the relative cardiovascular safety of psychedelic-assisted therapies in the population of "healthy" volunteers. However, there is insufficient evidence from therapies carried out with microdoses of psychedelics, and there is still a lack of data on the safety of psychedelics in the population of patients with cardiovascular disease. Therefore, the exact determination of the cardiovascular safety of psychedelic therapies (especially long-term therapies) requires further research.

A journey with psychedelic mushrooms: From historical relevance to biology, cultivation, medicinal uses, biotechnology, and beyond

Psychedelic mushrooms containing psilocybin and related tryptamines have long been used for ethnomycological purposes, but emerging evidence points to the potential therapeutic value of these mushrooms to address modern neurological, psychiatric health, and related disorders. As a result, psilocybin containing mushrooms represent a re-emerging frontier for mycological, biochemical, neuroscience, and pharmacology research. This work presents crucial information related to traditional use of psychedelic mushrooms, as well as research trends and knowledge gaps related to their diversity and distribution, technologies for quantification of tryptamines and other tryptophan-derived metabolites, as well as biosynthetic mechanisms for their production within mushrooms. In addition, we explore the current state of knowledge for how psilocybin and related tryptamines are metabolized in humans and their pharmacological effects, including beneficial and hazardous human health implications. Finally, we describe opportunities and challenges for investigating the production of psychedelic mushrooms and metabolic engineering approaches to alter secondary metabolite profiles using biotechnology integrated with machine learning. Ultimately, this critical review of all aspects related to psychedelic mushrooms represents a roadmap for future research efforts that will pave the way to new applications and refined protocols.

Association of Hallucinogen Persisting Perception Disorder with Trait Neuroticism and Mental Health Symptoms

Hallucinogen Persisting Perception Disorder (HPPD) is considered rare in hallucinogen users although there are conflicting reports about its incidence and prevalence. HPPD may be more common in those with trait neuroticism. In this study, we invited hallucinogen and other drug users to complete an online questionnaire about their use of hallucinogens, their experience of HPPD symptoms, and their trait neuroticism and mental health symptoms. We received 802 responses with 415 of these containing adequate data for further analysis. 39.7% of responders reported symptoms corresponding to Type I HPPD, and 4.3% reported symptoms corresponding to Type II HPPD. We found no significant difference between neuroticism scores for participants with or without HPPD. Individuals with Type II HPPD were more likely to report mental health symptoms including anxiety, obsessional thoughts, paranoia, hypochondria and panic attacks (p < .05). We also found that individuals with Type II HPPD were more likely to report the use of 25I-NBOMe, dextromethorphan, nitrous oxide and benzodiazepines (p < .05). 47.3% of participants had never tested their drugs, making the attribution of HPPD severity to specific drugs difficult. Further work into the development of HPPD is required, particularly with the rise of hallucinogens as potential treatments for depression and other mental illnesses.

Three Cases of Reported Improvement in Microsmia and Anosmia Following Naturalistic Use of Psilocybin and LSD

Cultural awareness of anosmia and microsmia has recently increased due to their association with COVID-19, though treatment for these conditions is limited. A growing body of online media claims that individuals have noticed improvement in anosmia and microsmia following classic psychedelic use. We report what we believe to be the first three cases recorded in the academic literature of improvement in olfactory impairment after psychedelic use. In the first case, a man who developed microsmia after a respiratory infection experienced improvement in smell after the use of 6 g of psilocybin containing mushrooms. In the second case, a woman with anosmia since childhood reported olfactory improvement after ingestion of 100 µg of lysergic acid diethylamide (LSD). In the third case, a woman with COVID-19-related anosmia reported olfactory improvement after microdosing 0.1 g of psilocybin mushrooms three times. Following a discussion of these cases, we explore potential mechanisms for psychedelic-facilitated improvement in olfactory impairment, including serotonergic effects, increased neuroplasticity, and anti-inflammatory effects. Given the need for novel treatments for olfactory dysfunction, increasing reports describing improvement in these conditions following psychedelic use and potential biological plausibility, we believe that the possible therapeutic benefits of psychedelics for these conditions deserve further investigation.

Psychedelic Science, Contemplative Practices, and Indigenous and Other Traditional Knowledge Systems: Towards Integrative Community-Based Approaches in Global Health

As individuals and communities around the world confront mounting physical, psychological, and social threats, three complimentary mind-body-spirit pathways toward health, wellbeing, and human flourishing remain underappreciated within conventional practice among the biomedical, public health, and policy communities. This paper reviews literature on psychedelic science, contemplative practices, and Indigenous and other traditional knowledge systems to make the case that combining them in integrative models of care delivered through community-based approaches backed by strong and accountable health systems could prove transformative for global health. Both contemplative practices and certain psychedelic substances reliably induce self-transcendent experiences that can generate positive effects on health, well-being, and prosocial behavior, and combining them appears to have synergistic effects. Traditional knowledge systems can be rich sources of ethnobotanical expertise and repertoires of time-tested practices. A decolonized agenda for psychedelic research and practice involves engaging with the stewards of such traditional knowledges in collaborative ways to codevelop evidence-based models of integrative care accessible to the members of these very same communities. Going forward, health systems could consider Indigenous and other traditional healers or spiritual guides as stakeholders in the design, implementation, and evaluation of community-based approaches for safely scaling up access to effective psychedelic treatments.

A Comprehensive Review of the Current Status of the Cellular Neurobiology of Psychedelics

Psychedelic substances have gained significant attention in recent years for their potential therapeutic effects on various psychiatric disorders. This review delves into the intricate cellular neurobiology of psychedelics, emphasizing their potential therapeutic applications in addressing the global burden of mental illness. It focuses on contemporary research into the pharmacological and molecular mechanisms underlying these substances, particularly the role of 5-HT2A receptor signaling and the promotion of plasticity through the TrkB-BDNF pathway. The review also discusses how psychedelics affect various receptors and pathways and explores their potential as anti-inflammatory agents. Overall, this research represents a significant development in biomedical sciences with the potential to transform mental health treatments.

Psychedelic use and psychiatric risks

RATIONALE

Research on psychedelics has recently shown promising results in the treatment of various psychiatric disorders, but relatively little remains known about the psychiatric risks associated with naturalistic use of psychedelics.

OBJECTIVE

The objective of the current study was to investigate associations between naturalistic psychedelic use and psychiatric risks.

METHODS

Using a sample representative of the US adult population with regard to sex, age, and ethnicity (N=2822), this study investigated associations between lifetime naturalistic psychedelic use, lifetime unusual visual experiences, and past 2-week psychotic symptoms.

RESULTS

Among respondents who reported lifetime psychedelic use (n=613), 1.3% reported having been told by a doctor or other medical professional that they had hallucinogen persisting perception disorder. In covariate-adjusted linear regression models, lifetime psychedelic use was associated with more unusual visual experiences at any point across the lifetime, but no association was observed between lifetime psychedelic use and past 2-week psychotic symptoms. There was an interaction between lifetime psychedelic use and family (but not personal) history of psychotic or bipolar disorders on past 2-week psychotic symptoms such that psychotic symptoms were highest among respondents who reported lifetime psychedelic use and a family history of psychotic or bipolar disorders and lowest among those who reported lifetime psychedelic use and no family history of psychotic or bipolar disorders.

CONCLUSIONS

Although the results in this study should be interpreted with caution, the findings suggest that lifetime naturalistic use of psychedelics might be associated with more unusual visual experiences across the lifetime, as well as more psychotic symptoms in the past 2 weeks for individuals with a family history of psychotic or bipolar disorders and the reverse for those without such a family history. Future research should distinguish between different psychotic and bipolar disorders and should also utilize other research designs (e.g., longitudinal) and variables (e.g., polygenic risk scores) to better understand potential cause-and-effect relationships.

Extended difficulties following the use of psychedelic drugs: A mixed methods study

Long-term adverse experiences following psychedelic use can persist for weeks, months, or even years, and are relatively unexplored in psychedelic research. Our convergent mixed-method study gained quantitative and qualitative data from 608 participants who reported extended difficulties following psychedelic experiences. Data was gathered on the context of use, the nature and duration of the challenges they experienced (including a written description of these), plus a range of possible risk factors and perceived causes. The most common forms of extended difficulty were feelings of anxiety and fear, existential struggle, social disconnection, depersonalization and derealization. For approximately one-third of the participants, problems persisted for over a year, and for a sixth, they endured for more than three years. It was found that a shorter duration of difficulties was predicted by knowledge of dose, drug type and lower levels of difficulty reported during the psychoactive experience, while a narrower range of difficulties was predicted by taking the drug in a guided setting. Implications for psychedelic harm reduction are discussed.