Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction

Classic psychedelics and the treatment for alcoholism

Alcohol is a harmful drug, and reducing its consumption is a significant challenge for users. Furthermore, alcohol dependence is often treatment-resistant, and no completely effective treatment model is available for chemical dependence. Classic psychedelics, such as LSD, psilocybin, and ayahuasca have been used in different clinical and pre-clinical trials, demonstrating promising pharmacotherapeutic effects in the treatment of treatment-resistant psychopathological conditions, such as addiction, especially related to alcohol dependence. In this work, we conducted a narrative review of the emerging research regarding the potential of psychedelics for alcohol use disorder treatment. Psychedelic substances have demonstrated potential for treating drug addiction, especially AUD, mostly by modulating neuroplasticity in the brain. Given that serotonergic psychedelics do not produce physical dependence or withdrawal symptoms with repeated use, they may be considered promising treatment options for managing drug use disorders. However, certain limitations could be found. Although many participants achieve positive results with only one treatment dose in clinical studies, great inter-individual variability exists in the duration of these effects. Therefore, further studies using different doses and experimental protocols should be conducted to enhance evidence about psychedelic substances.

Masking Influences: A Systematic Review of Placebo Control and Masking in Psychedelic Studies

Psychedelic-assisted therapy is becoming increasingly acknowledged as an effective therapeutic intervention for various psychiatric illnesses. However, the evaluation of masking success is rarely reported in trials. The objective of the present systematic review was to evaluate placebo-control and masking in studies exploring psychedelic-assisted therapy. Nine (k = 9) studies dating between January 2010 and March 2023 were retrieved using six databases, following strict inclusion and exclusion criteria. The results show that almost 78% of the studies had, at best, "poor" masking success. At the same time, 60% of active placebo and 75% of inactive placebo studies showed large effect sizes. In other words, masking influences, including benign unmasking, cannot be excluded. We therefore conclude that efficacy of psilocybin, Ayahuasca, or LSD is only one of the possible interpretations of large, positive changes in symptomatology for patients suffering from, for example, alcohol use disorder, anxiety with or without life-threatening disease, anxiety and/or depression with life-threatening cancer, treatment-resistant depression or major depressive disorder. We recommend care be taken to increase successful masking procedures and discuss alternative treatment designs to better control for potential masking influences.

The molecular structure, vibrational spectra, solvation effect, non-covalent interactions investigations of psilocin

Psilocin, or 4-HO-DMT (or 3-(2-dimethylaminoethyl)-1H-indol-4-ol), is a psychoactive alkaloid substance from the tryptamine family, isolated from Psilocybe mushrooms. This substance is being studied by various research groups because it has a clear therapeutic effect in certain dosages. In this work, the study of the structure and properties of psilocin was carried using theoretical methods: the effects of polar solvents (acetonitrile, dimethylsulfoxide, water, and tetrahydrofuran) on the structural parameters, spectroscopic properties (Raman, IR, and UV-Vis), frontier molecular orbital (FMO), molecular electrostatic potential (MEP) surface, and nonlinear optical parameters (NLO). Theoretical calculations were performed at the B3LYP/6-311++G(d,p) level by the density functional theory (DFT) method. IEFPCM was used to account for solvent effects. The types and nature of non-covalent interactions (NCI) between psilocin and solvent molecules were determined using Atoms in Molecules (AIM), the reduced density gradient method (RDG), the electron localization function (ELF), and the localization orbital locator (LOL). Experimental and calculated FT-IR, FT-Raman, and UV-Vis spectra were compared and found to be in good agreement.

Does the Perception of Risk Associated with Psychedelics Use Differ in Physicians According to Their Belief of Effectiveness?

The aim of this study was to explore the perception of psychedelics within the medical population. Participants were asked by questionnaire about the potential of abuse, the somatic and psychiatric complications, and the risks of self-harm and aggression associated with the use of psychedelics using Likert Scales. A total of 407 participants were included. In our sample, the following means were found: 3.05 for general risk (<.001), 2.68 for self-harm risk (<.001), 2.47 for aggression (<.001), 2.71 for addictive risk (< .001), 2.76 for psychiatric disorder risk (<.001), and 2.11 for somatic disorder(< .001). Physicians from the lower mean of age were significantly more supportive of therapeutic potential, while general practitioners were significantly less likely to consider psychedelics as a treatment than specialists (<.001). By the term therapeutic potential, we meant the therapeutic value attributable to psychedelics and the risks expressed the possibility of damage caused by the use of the drug. Clinicians who considered psychedelics as a potential treatment were less likely to associate these with risks than their counterparts (<.001). The results of this study show that the perception of the danger of psychedelic use was important in the medical community in France.

Examining differences in the effects and contexts of naturalistic psilocybin use for White participants vs. Participants of Color: A longitudinal online survey study

BACKGROUND

Psilocybin (a psychoactive compound found in "magic mushrooms" or "shrooms") has been gaining increased attention in research and popular culture as a number of clinical and observational studies have demonstrated that it may have potential for improving mental wellbeing. Relatedly, there has been a substantial uptick in naturalistic (e.g., real-world, non-clinical) psilocybin use in the United States. While a number of longitudinal studies have demonstrated that naturalistic psilocybin use is linked to positive mental health outcomes on average, few studies have examined how the effects of psilocybin and contexts for psilocybin use may differ for White populations compared to Populations of Color.

OBJECTIVE

To examine differences in health outcomes, subjective effects, and contexts of naturalistic psilocybin use in White participants compared to Participants of Color.

METHODS

This study used data from a large, online longitudinal study of individuals who planned to engage in naturalistic psilocybin use (N = 2833). We used mixed-effects models to assess whether race/ethnicity (White vs. Participant of Color) moderated associations between time (Time 2 [initial assessment point for longitudinal measures], Time 5 [2-4 weeks post-psilocybin experience, and Time 6 [2-3 months post-experience]) and outcomes related to mental health (depression, anxiety, spiritual wellbeing, cognitive flexibility, emotion regulation [expressive suppression + cognitive reappraisal]). We also used exploratory chi-squared tests to examine differences in contexts for psilocybin use as well as differences in subjective effects related to the psilocybin experience.

RESULTS

Race/ethnicity moderated the associations between time for predicting spiritual wellbeing (beta = -1.8; 95 % CI [-3.4, -0.17]; p < 0.05), cognitive flexibility (beta = -1.5 [-2.7, -0.26]; p < 0.05), and emotion regulation - expressive suppression (beta = 0.25 [0.06, 0.44]; p < 0.05) at Time 6 (but not Time 5). Additionally, Participants of Color reported minor differences in subjective effects and context for use compared to White participants (e.g., more likely to have set an intention prior to use, report time speeding up during the experience, etc.). We found reductions in anxiety and depression for both Participants of Color and White participants, and our moderation tests for these outcomes were not significant.

CONCLUSION

Race/ethnicity impacts the associations between psilocybin use and various markers of mental wellbeing. Future longitudinal studies and experimental studies with larger samples of color can further elucidate the preliminary findings from this study.

Pharmacological and behavioural effects of tryptamines present in psilocybin-containing mushrooms

BACKGROUND AND PURPOSE

Demand for new antidepressants has resulted in a re-evaluation of the therapeutic potential of psychedelic drugs. Several tryptamines found in psilocybin-containing "magic" mushrooms share chemical similarities with psilocybin. Early work suggests they may share biological targets. However, few studies have explored their pharmacological and behavioural effects.

EXPERIMENTAL APPROACH

We compared baeocystin, norbaeocystin and aeruginascin with psilocybin to determine if they are metabolized by the same enzymes, similarly penetrate the blood-brain barrier, serve as ligands for similar receptors and modulate behaviour in rodents similarly. We also assessed the stability and optimal storage and handling conditions for each compound.

KEY RESULTS

In vitro enzyme kinetics assays found that all compounds had nearly identical rates of dephosphorylation via alkaline phosphatase and metabolism by monoamine oxidase. Further, we found that only the dephosphorylated products of baeocystin and norbaeocystin crossed a blood-brain barrier mimetic to a similar degree as the dephosphorylated form of psilocybin, psilocin. The dephosphorylated form of norbaeocystin was found to activate the 5-HT2A receptor with similar efficacy to psilocin and norpsilocin in in vitro cell imaging assays. Behaviourally, only psilocybin induced head twitch responses in rats, a marker of 5-HT2A-mediated psychedelic effects and hallucinogenic potential. However, like psilocybin, norbaeocystin improved outcomes in the forced swim test. All compounds caused minimal changes to metrics of renal and hepatic health, suggesting innocuous safety profiles.

CONCLUSIONS AND IMPLICATIONS

Collectively, this work suggests that other naturally occurring tryptamines, especially norbaeocystin, may share overlapping therapeutic potential with psilocybin, but without causing hallucinations.

Prevalence of psilocybin use in vaping and associated factors: a study among amphetamine-type stimulants (ATS) use disorder in Malaysia

BACKGROUND

The emergence of New Psychoactive Substances (NPS), including synthetic psilocybin, has raised concern among health experts due to the numerous health and socioeconomic consequences. The current trend is shifting to the hazardous use of synthetic psilocybin in vaping, and little is known about the prevalence of use, specifically among amphetamine-type stimulants (ATS) users.

METHODS

Interviewer-administered questionnaires were conducted in drug detention centers between March and October 2022. The study was conducted using ASSIST 3.0 and obtained information on the respondents' socio-demographic characteristics and clinical profiles. N = 355 ATS users were enrolled in this study.

RESULTS

The results show a high prevalence of psilocybin vaping among ATS users (182/355, 53.1%). Most of the respondents were males (85.1%) and unmarried (69.3%), with a mean age of 29.2 (SD = 7.3). Across all respondents, five factors were associated with psilocybin vaping: tobacco smoking, aOR =5.790 (95% CI: 1.723, 8.183); cannabis uses, aOR= 9.152 (95% CI: 2.693, 10.396); and alcohol use, aOR= 3.137 (95% CI: 1.461, 5.817). Respondents of the Malay race had higher odds of being involved in psilocybin vaping compared to other races, with aOR= 1.638 (0.043, 2.459). Meanwhile, a reduction in age by 1.9 will increase the likelihood of involvement in psilocybin vaping with aOR = 1.897 (95% CI: 0.857, 1.938).

CONCLUSION

Psilocybin in vaping is growing among ATS users and across all populations. Unfortunately, knowledge regarding the long-term effects on health is limited. Further studies should highlight the harmful effects of psilocybin and the potential risk of psilocybin vaping among the younger population.

Less is more? A review of psilocybin microdosing

BACKGROUND

The applications of psilocybin, derived from 'magic mushrooms,' are vast, including a burgeoning practice known as microdosing, which refers to the administration of sub-hallucinogenic doses of psychedelic substances to obtain benefits without experiencing significant cognitive and perceptual distortion. However, current research is fairly new with several limitations and gaps that hinder adequate conclusions on its efficacy.

AIMS

This semi-structured review aimed to identify and highlight research gaps in the field of psilocybin microdosing for future research.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses based strategy was employed, utilizing a chain of keywords and key phrases across multiple databases, augmented by a cross-sectional Google search for relevant grey literature in the form of the top 10 search results. A total of 40 studies and 8 unique websites were identified, summarized and tabulated into four distinct categories, namely non-clinical, clinical, observational and anecdotal evidence.

RESULTS

The majority of available evidence originates from observational studies, while non-clinical and clinical study findings remain comparatively sparse and inconsistent. Web-based findings were consistent with current research findings. Key research gaps were highlighted: the imperative for more randomized placebo-controlled trials, exploration of dose-response ranges, psychological and personality testing of participants, utilization of active placebos, greater diversity in study populations, an increase in psilocybin-exclusive microdosing studies and the refinement of animal models.

CONCLUSION

Definitive conclusions regarding the efficacy of psilocybin microdosing remain elusive, emphasizing the need for further study. Numerous research gaps necessitate consideration for future investigations.

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.

Single-dose psilocybin for U.S. military Veterans with severe treatment-resistant depression - A first-in-kind open-label pilot study

BACKGROUND

The enduring and severe depression often suffered by Veterans causes immense suffering and is associated with high rates of suicide and disability. This is the first study to evaluate the efficacy and safety of psilocybin in Veterans with severe treatment-resistant depression (TRD).

METHODS

15 Veterans with severe TRD (major depressive episode failing to respond to ≥5 treatments, or lasting >2 years) received 25 mg of psilocybin. Primary outcome was change in Montgomery-Åsberg Depression Rating scale (MADRS) at 3 weeks posttreatment. Response was defined s ≥ 50 % reduction in MADRS, and remission as ≤10 MADRS score. Psychedelic experience was assessed using the Five-Dimensional Altered States of Consciousness scale (5D-ASC). Safety measures included assessment of suicidality and adverse events. Participants on antidepressants were tapered to avoid drug interactions.

RESULTS

Of 15 participants, 60 % met response and 53 % met remission criteria at Week 3. At 12 weeks, 47 % maintained response, and 40 % remission. Co-morbid PTSD did not significantly influence study outcomes. The psychedelic experience reported in 5D-ASC did not correlate with response. Participants judged to need antidepressants were restarted and considered non-responders from that timepoint (n = 4). No unexpected adverse events occurred.

LIMITATIONS

Limitations include the small sample size, and the uncontrolled and unblinded nature of the study.

CONCLUSIONS

In this first study on psilocybin for Veterans with severe TRD, a surprising response and remission was seen. Many Veterans had PTSD though no moderating impact of response was observed. The degree of psychedelic experience did not correlate with depression changes. Further study is warranted.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04433858.

Validation of the imperial psychedelic predictor scale

BACKGROUND

Access to psychedelic drugs is liberalizing, yet responses are highly unpredictable. It is therefore imperative that we improve our ability to predict the nature of the acute psychedelic experience to improve safety and optimize potential therapeutic outcomes. This study sought to validate the 'Imperial Psychedelic Predictor Scale' (IPPS), a short, widely applicable, prospective measure intended to be predictive of salient dimensions of the psychedelic experience.

METHODS

Using four independent datasets in which the IPPS was completed prospectively - two online surveys of 'naturalistic' use (N = 741, N = 836) and two controlled administration datasets (N = 30, N = 28) - we conducted factor analysis, regression, and correlation analyses to assess the construct, predictive, and convergent validity of the IPPS.

RESULTS

Our approach produced a 9-item scale with good internal consistency (Cronbach's α = 0.8) containing three factors: set, rapport, and intention. The IPPS was significantly predictive of 'mystical', 'challenging', and 'emotional breakthrough' experiences. In a controlled administration dataset (N = 28), multiple regression found set and rapport explaining 40% of variance in mystical experience, and simple regression found set explained 16% of variance in challenging experience. In another (N = 30), rapport was related to emotional breakthrough explaining 9% of variance.

CONCLUSIONS

Together, these data suggest that the IPPS is predictive of relevant acute features of the psychedelic experience in a broad range of contexts. We hope that this brief 9-item scale will be widely adopted for improved knowledge of psychedelic preparedness in controlled settings and beyond.

Psychedelics: From Cave Art to 21st-Century Medicine for Addiction

BACKGROUND

Psychedelic substance use in ritualistic and ceremonial settings dates back as early as 8,500 BCE. Only in recent years, from the mid-20th century, we have seen the re-emergence of psychedelics in a therapeutic setting and more specifically for the treatment of addiction. This article aims to review research over the past 40 years using classic (psilocybin, lysergic acid diethylamide [LSD], dimethyltryptamine [DMT], mescaline) and atypical (ketamine, ibogaine, 5-MeO-DMT, 3,4-methylenedioxymethamphetamine) psychedelics for the treatment of addiction.

SUMMARY

We will start with an overview of the pharmacology and physiological and psychological properties of psychedelic substances from pre-clinical and clinical research. We will then provide an overview of evidence gathered by studies conducted in controlled research environments and naturalistic and ceremonial settings, while we identify the proposed therapeutic mechanisms of each psychedelic substance.

KEY MESSAGES

Classic and atypical psychedelics show promise as therapeutic alternatives for the treatment of addiction, through the improvement of psychological and physiological symptoms of dependence. A more comprehensive understanding of the ancient and present-day knowledge of the therapeutic potential of psychedelics can facilitate hope for psychedelic therapeutics in the treatment of addiction, especially for individuals who have failed other conventional treatment methods.

Psychedelics as a potential treatment for tobacco use disorder: a systematic review

INTRODUCTION

Despite considerable efforts, tobacco use disorder persists as a significant public health issue. The effectiveness of current smoking cessation therapies is limited, leading to a growing interest in alternative treatment approaches such as psychedelics.

AIM

The aim of this review is to evaluate the scientific evidence regarding the role of psychedelics in smoking cessation.

METHODS

To identify relevant literature on psychedelics and smoking cessation, a search was conducted in four academic literature databases PubMed, MEDLINE, PsycINFO, and Embase. Databases were searched from their inception up to March 24, 2024.

RESULTS

Out of the 1073 articles identified in databases, 8 publications (both clinical and non-clinical studies) met the inclusion criteria, of which a total of 4 publications originated from a single study. The majority of the studies focused on psilocybin (n = 7), for which supportive evidence was suggested for the treatment of tobacco use disorder. Additionally, research was conducted with other psychedelics for smoking cessation, such as ayahuasca, mescaline, peyote, lysergic acid diethylamide (LSD), lysergic acid amide (LSA) and (dimethyltryptamine (DMT), but the evidence base for these psychedelics is too small to draw definitive conclusions.

CONCLUSIONS

There is, although limited, evidence that psychedelics, in particular psilocybin, may offer a potential avenue for combating tobacco use disorder, though more research is needed to understand their effectiveness and safety fully.

Personal Psychedelic Experience as a Training Qualification for Facilitators: A Thematic Analysis of Qualitative Interviews with Psilocybin Experts

Emerging legal frameworks in Oregon and Colorado license facilitators to support adults receiving psychedelic services. The current legal frameworks are silent regarding facilitators' personal experience with psychedelics. An e-Delphi process recruited 36 experts with at least 5 years' experience facilitating psilocybin experiences in ceremonial settings, indigenous practices, or clinical trials. Respondents completed in-depth, semi-structured qualitative interviews via secure web links. Interviews were recorded, transcribed, and analyzed using Thematic Analysis. Experts with a mean of 15.2 (SD 13.1) years' experience providing psilocybin services expressed the importance of first-hand experience with psychedelics as a qualification for the emerging workforce. One participant questioned the necessity of personal psychedelic experience. Experts suggested that personal experience may indirectly support high-quality care because it enhances facilitators' personal wellbeing, and may help facilitators understand the complexity and nature of their clients' psychedelic experiences. Novel state-legal psychedelic paradigms create a real-world opportunity to assess associations between facilitators' personal psychedelic experience and the safety and outcomes of psychedelic services.

Co-administration of midazolam and psilocybin: differential effects on subjective quality versus memory of the psychedelic experience

Aspects of the acute experience induced by the serotonergic psychedelic psilocybin predict symptomatic relief in multiple psychiatric disorders and improved well-being in healthy participants, but whether these therapeutic effects are immediate or are based on memories of the experience is unclear. To examine this, we co-administered psilocybin (25 mg) with the amnestic benzodiazepine midazolam in 8 healthy participants and assayed the subjective quality of, and memory for, the dosing-day experience. We identified a midazolam dose that allowed a conscious psychedelic experience to occur while partially impairing memory for the experience. Furthermore, midazolam dose and memory impairment tended to associate inversely with salience, insight, and well-being induced by psilocybin. These data suggest a role for memory in therapeutically relevant behavioral effects occasioned by psilocybin. Because midazolam blocks memory by blocking cortical neural plasticity, it may also be useful for evaluating the contribution of the pro-neuroplastic properties of psychedelics to their therapeutic activity.

Psychedelic-assisted therapy for treating anxiety, depression, and existential distress in people with life-threatening diseases

BACKGROUND

Psychedelic-assisted therapy refers to a group of therapeutic practices involving psychedelics taken under therapeutic supervision from physicians, psychologists, and others. It has been hypothesised that psychedelic-assisted therapy may reduce symptoms of anxiety, depression, and existential distress in patients facing life-threatening diseases (e.g. cancer). However, these substances are illegal in most countries and have been associated with potential risks.

OBJECTIVES

To assess the benefits and harms of psychedelic-assisted therapy compared to placebo or active comparators (e.g. antidepressants) for treatment of anxiety, depression, and existential distress in people with life-threatening diseases.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and two trial registers on 30 March 2024. In addition, we undertook reference checking, citation searching, and contact with study authors to identify additional studies. We used no language or date restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), with no restrictions regarding comorbidity, sex, or ethnicity. Interventions comprised a substance-induced psychedelic experience preceded by preparatory therapeutic sessions and followed by integrative therapeutic sessions.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included six studies in the review, which evaluated two different interventions: psychedelic-assisted therapy with classical psychedelics (psilocybin ('magic mushrooms') and lysergic acid diethylamide (LSD)), and psychedelic-assisted therapy with 3,4-methylenedioxymethamphetamine (MDMA or 'Ecstasy'). The studies randomised 149 participants with life-threatening diseases and analysed data for 140 of them. The age range of participants was 36 to 64 years. The studies lasted between 6 and 12 months, and were conducted in outpatient settings in the USA and in Switzerland. Drug companies were not involved in study funding, but funding was provided by organisations that promote psychedelic-assisted therapy. Primary outcomes (at 1 to 12 weeks) Anxiety Psychedelic-assisted therapy using classical psychedelics (psilocybin, LSD) may result in a reduction in anxiety when compared to active placebo (or low-dose psychedelic): State Trait Anxiety Inventory (STAI-Trait, scale 20 to 80) mean difference (MD) -8.41, 95% CI -12.92 to -3.89; STAI-State (scale 20 to 80) MD -9.04, 95% CI -13.87 to -4.21; 5 studies, 122 participants; low-certainty evidence. The effect of psychedelic-assisted therapy using MDMA on anxiety, compared to placebo, is very uncertain: STAI-T MD -14.70, 95% CI -29.45 to 0.05; STAI-S MD -16.10, 95% CI -33.03 to 0.83; 1 study, 18 participants; very low certainty evidence. Depression Psychedelic-assisted therapy using classical psychedelics (psilocybin, LSD) may result in a reduction in depression when compared to active placebo (or low-dose psychedelic): Beck Depression Inventory (BDI, scale 0 to 63) MD -4.92, 95% CI -8.97 to -0.87; 4 studies, 112 participants; standardised mean difference (SMD) -0.43, 95% CI -0.79 to -0.06; 5 studies, 122 participants; low-certainty evidence. The effect of psychedelic-assisted therapy using MDMA on depression, compared to placebo, is very uncertain: BDI-II (scale: 0 to 63) MD -6.30, 95% CI -16.93 to 4.33; 1 study, 18 participants; very low certainty evidence. Existential distress Psychedelic-assisted therapy using classical psychedelics (psilocybin, LSD) compared to active placebo (or low-dose psychedelic) may result in a reduction in demoralisation, one of the most common measures of existential distress, but the evidence is very uncertain (Demoralisation Scale, 1 study, 28 participants): post treatment scores, placebo group 39.6 (SEM 3.4), psilocybin group 18.8 (3.6), P ≤ 0.01). Evidence from other measures of existential distress was mixed. Existential distress was not measured in people receiving psychedelic-assisted therapy with MDMA. Secondary outcomes (at 1 to 12 weeks) Quality of life When classical psychedelics were used, one study had inconclusive results and two reported improved quality of life, but the evidence is very uncertain. MDMA did not improve quality of life measures, but the evidence is also very uncertain. Spirituality Participants receiving psychedelic-assisted therapy with classical psychedelics rated their experience as being spiritually significant (2 studies), but the evidence is very uncertain. Spirituality was not assessed in participants receiving MDMA. Adverse events No treatment-related serious adverse events or adverse events grade 3/4 were reported. Common minor to moderate adverse events for classical psychedelics were elevated blood pressure, nausea, anxiety, emotional distress, and psychotic-like symptoms (e.g. pseudo-hallucination where the participant is aware they are hallucinating); for MDMA, common minor to moderate adverse events were anxiety, dry mouth, jaw clenching, and headaches. Symptoms subsided when drug effects wore off or up to one week later. Certainty of the evidence Although all six studies had intended to blind participants, personnel, and assessors, blinding could not be achieved as this is very difficult in studies investigating psychedelics. Using GRADE criteria, we judged the certainty of evidence to be low to very low, mainly due to high risk of bias and imprecision (small sample size).

AUTHORS' CONCLUSIONS

Implications for practice Psychedelic-assisted therapy with classical psychedelics (psilocybin, LSD) may be effective for treating anxiety, depression, and possibly existential distress, in people facing a life-threatening disease. Psychedelic-assisted therapy seemed to be well tolerated, with no treatment-emergent serious adverse events reported in the studies included in this review. However, the certainty of evidence is low to very low, which means that we cannot be sure about these results, and they might be changed by future research. At the time of this review (2024), psychedelic drugs are illegal in many countries. Implications for research The risk of bias due to 'unblinding' (participants being aware of which intervention they are receiving) could be reduced by measuring expectation bias, checking blinding has been maintained before cross-over, and using active placebos. More studies with larger sample sizes are needed to reduce imprecision. As the US Drug Enforcement Administration (DEA) currently classifies psychedelics as Schedule I substances (i.e. having no accepted medical use and a high potential for abuse), research involving these drugs is restricted, but is steadily increasing.

Pharmacokinetics of Psilocybin, a Tryptamine Alkaloid in Magic Mushroom (Psilocybe cubensis): A Systematic Review

Psilocybin, a major indole alkaloid found in magic mushrooms (Psilocybe cubensis), has recently drawn attention as a breakthrough therapy to treat major depressive disorder. This review aimed to summarize and identify knowledge gaps concerning their pharmacokinetic characteristics of psilocybin and its active metabolite, psilocin. Original studies related to pharmacokinetics of psilocybin conducted in vitro, animals, and humans were systematically collected from PubMed, Scopus, and ScienceDirect, from their inceptions to November 2023. Twenty articles were included in this work and assessed for study quality. A comprehensive review of the pharmacokinetics of psilocybin and psilocin in both animals and humans was performed. Psilocybin is considered a prodrug that is dephosphorylated to psilocin by alkaline phosphatase. Following ingestion, the peak psilocin plasma and brain levels were rapidly achieved in a dose-dependent manner. Psilocin is metabolized primarily through both Phase I and Phase II processes with the half-life of 2-3 hours. This review also identified lack of some pharmacokinetic related information and limitations of available research that may help direct future investigations to better understand the pharmacokinetics and improve study design including dose selection and dosage optimization.

Pharmacological and non-pharmacological predictors of the LSD experience in healthy participants

The pharmacodynamic effects of lysergic acid diethylamide (LSD) are diverse and different in different individuals. Effects of other psychoactive substances have been shown to be critically influenced by non-pharmacological factors such as personality traits and mood states. The aim of this study was to determine pharmacological and psychological predictors of the LSD effects in healthy human subjects. This analysis is based on nine double-blind, placebo-controlled, cross-over studies with a total of 213 healthy subjects receiving between 25-200 µg LSD. The influence of sex, age, dose, body weight, pharmacogenetic, drug experience, personality, setting, and mood before drug intake on the peak autonomic and total subjective responses to LSD was investigated using multiple linear mixed effects models and Least Absolute Shrinkage and Selection Operator regression. Results were adjusted for LSD dose and corrected for multiple testing. LSD dose emerged as the most influential predictor, exhibiting a positive correlation with most response variables. Pre-drug mental states such as "Well-Being", "Emotional Excitability", and "Anxiety" were also important predictor for a range of subjective effects but also heart rate and body temperature. The trait "Openness to Experiences" was positively correlated with elevated ratings in "Oceanic Boundlessness" and mystical-type effects. Previous experiences with hallucinogens have been negatively associated with the overall altered state of consciousness and particularly with "Anxious Ego Dissolution". Acute anxiety negatively correlated with the genetically determined functionality of the Cytochrome 2D6 enzyme. In summary, besides the amount of drug consumed, non-pharmacological factors such as personal traits and current mood also significantly predicted the subjective drug experience. Sex and body weight were not significant factors in influencing the drug experience.

Mind over matter: the microbial mindscapes of psychedelics and the gut-brain axis

Psychedelics have emerged as promising therapeutics for several psychiatric disorders. Hypotheses around their mechanisms have revolved around their partial agonism at the serotonin 2 A receptor, leading to enhanced neuroplasticity and brain connectivity changes that underlie positive mindset shifts. However, these accounts fail to recognise that the gut microbiota, acting via the gut-brain axis, may also have a role in mediating the positive effects of psychedelics on behaviour. In this review, we present existing evidence that the composition of the gut microbiota may be responsive to psychedelic drugs, and in turn, that the effect of psychedelics could be modulated by microbial metabolism. We discuss various alternative mechanistic models and emphasize the importance of incorporating hypotheses that address the contributions of the microbiome in future research. Awareness of the microbial contribution to psychedelic action has the potential to significantly shape clinical practice, for example, by allowing personalised psychedelic therapies based on the heterogeneity of the gut microbiota.

Distinct 5-HT receptor subtypes regulate claustrum excitability by serotonin and the psychedelic, DOI

Recent evidence indicates that neuronal activity within the claustrum (CLA) may be central to cellular and behavioral responses to psychedelic hallucinogens. The CLA prominently innervates many cortical targets and displays exceptionally high levels of serotonin (5-HT) binding. However, the influence of serotonin receptors, prime targets of psychedelic drug action, on CLA activity remains unexplored. We characterize the CLA expression of all known 5-HT subtypes and contrast the effects of 5-HT and the psychedelic hallucinogen, 2,5-dimethoxy-4-iodoamphetamine (DOI), on excitability of cortical-projecting CLA neurons. We find that the CLA is particularly enriched with 5-HT2C receptors, expressed predominantly on glutamatergic neurons. Electrophysiological recordings from CLA neurons that project to the anterior cingulate cortex (ACC) indicate that application of 5-HT inhibits glutamate receptor-mediated excitatory postsynaptic currents (EPSCs). In contrast, application of DOI stimulates EPSCs. We find that the opposite effects of 5-HT and DOI on synaptic signaling can both be reversed by inhibition of the 5-HT2C, but not 5-HT2A, receptors. We identify specific 5-HT receptor subtypes as serotonergic regulators of the CLA excitability and argue against the canonical role of 5-HT2A in glutamatergic synapse response to psychedelics within the CLA-ACC circuit.

Translation and Initial Psychometric Evaluation of Spanish Versions of Three Psychedelic Acute Effects Measures: Mystical, Challenging, and Insight Experiences

This study translated and tested the psychometric properties of acute psychedelic effects measures among Spanish-speaking people. The Psychological Insight Questionnaire (PIQ), Challenging Experiences Questionnaire (CEQ), and Mystical Experiences Questionnaire (MEQ) were translated before being incorporated into a web-based survey. We recruited native Spanish-speakers (N = 442; Mage = 30.8, SD = 10.9; Latino/Latina = 62%; Hispanic = 91.4%; male = 71.5%) to assess their previous experience with one of two psychedelics (LSD = 58.4%; Psilocybin = 41.6%) and their acute and enduring effects. Confirmatory factor analysis (confirming factor structure based on the English version) revealed a good fit for the MEQ, PIQ and the CEQ. Repeating our analysis in each drug subsample revealed consistency in factor structure for each assessment tool. Construct validity was supported by significant positive associations between the PIQ and MEQ, and between the PIQ and MEQ and changes in cognitive fusion and negative associations between changes in prosocial behaviors. As a signal of predictive validity, persisting effects (PEQ) were strongly related to scores on the MEQ and PIQ. Findings demonstrate that the Spanish versions of these measures can be reliably employed in studies of psychedelic use or administration in Spanish-speaking populations.

Development of the Japanese version of the Challenging Experience Questionnaire

INTRODUCTION

The therapeutic potential of psychedelics for various mental disorders has gained significant interest. Previous studies have highlighted that psychedelics induce psychoactive effects, including challenging aspects of experiences. These experiences are assessed using the Challenging Experience Questionnaire (CEQ), yet its Japanese version has been unavailable. This study aimed to create a Japanese version of the CEQ.

METHODS

We followed the "Principles of Good Practice for the Translation and Cultural Adaptation Process for Patient-Reported Outcomes (PRO) Measures: Report of the ISPOR Task Force for Translation and Cultural Adaptation." Initially, two Japanese psychiatrists independently conducted the forward translations. These were then reconciled into a single version, which was back-translated into English. The original authors reviewed this back-translation for accuracy, leading to revisions through continuous dialogue until the original authors approved the final version.

RESULTS

The final, approved back-translated version of the CEQ is presented in the figure.

CONCLUSIONS

This study developed a Japanese version of the CEQ, enabling the assessment of challenging experiences during psychedelic-assisted therapy for Japanese speakers. Further studies are needed to assess the reliability and validity of this newly translated version.

Psilocybin as a lead candidate molecule in preclinical therapeutic studies of psychiatric disorders: A systematic review

Psilocybin is the main psychoactive compound found in hallucinogenic/magic mushrooms and can bind to both serotonergic and tropomyosin receptor kinase b (TrkB) receptors. Psilocybin has begun to show efficacy for a range of neuropsychiatric conditions, including treatment-resistant depression and anxiety disorders; however, neurobiological mechanisms are still being elucidated. Clinical research has found that psilocybin can alter functional connectivity patterns in human brains, which is often associated with therapeutic outcomes. However, preclinical research affords the opportunity to assess the potential cellular mechanisms by which psilocybin may exert its therapeutic effects. Preclinical rodent models can also facilitate a more tightly controlled experimental context and minimise placebo effects. Furthermore, where there is a rationale, preclinical researchers can investigate psilocybin administration in neuropsychiatric conditions that have not yet been researched clinically. As a result, we have systematically reviewed the knowledge base, identifying 82 preclinical studies which were screened based on specific criteria. This resulted in the exclusion of 44 articles, with 34 articles being included in the main review and another 2 articles included as Supporting Information materials. We found that psilocybin shows promise as a lead candidate molecule for treating a variety of neuropsychiatric conditions, albeit showing the most efficacy for depression. We discuss the experimental findings, and identify possible mechanisms whereby psilocybin could invoke therapeutic changes. Furthermore, we critically evaluate the between-study heterogeneity and possible future research avenues. Our review suggests that preclinical rodent models can provide valid and translatable tools for researching novel psilocybin-induced molecular and cellular mechanisms, and therapeutic outcomes.

Exploring psychedelic use in athletes and their attitudes toward psilocybin-assisted therapy in concussion recovery

Background

Psychedelics are receiving growing interest among clinical researchers for their effects on mood and cognition. Psilocybin is one of the most widely studied classic psychedelics which has shown good safety and clinical benefit for major depression and substance use disorders. Athletes frequently sustain concussions and often experience myriad symptoms, including cognitive and mood issues, which can persist for weeks or months in 10%-30% of athletes. Psilocybin may be a potential symptom management option for athletes with persisting concussion symptoms.

Objectives

This study sought to summarize athlete psychedelic use, among other substances, and to examine the willingness of the sports community to engage in or support psilocybin-assisted therapy (PAT) for concussion recovery and management of persisting concussion symptoms.

Methods

In total, 175 (n = 85 athletes; n = 90 staff) respondents completed an online survey distributed in Canada and the United States which queried sport involvement and demographics, substance use, concussion history, and knowledge and willingness about psilocybin. The reporting of this study conforms to the Checklist for Reporting Results of Internet E-Surveys (CHERRIES) statement.

Design

Substance use rates were summarized across athletes and team staff members and a path analysis was used for each sample to identify predictors of willingness to use PAT (athletes) or support PAT (staff) for concussion recovery. Participants were also asked to identify perceived barriers to the implementation of PAT for sports-related concussions, and to indicate their overall willingness.

Results

Psychedelics were the third most used substance in the past year among athletes (35.8%) while regular psychedelic use was quite low in athletes (7.5%). A path analysis conducted in RStudio found that attitudes toward psilocybin and knowledge of psilocybin were significant predictors for both athletes and staff members of their willingness to use or support PAT for concussion recovery. Athletes reported likely engaging in PAT (61.2%) and staff (71.1%) reported that they would support their athletes using PAT.

Conclusion

The results of this study suggest that the sports community may be receptive to PAT and athletes would be willing to engage in it for concussion recovery and/or the management of persisting post-concussion symptoms (PPCS). Future research should examine the effects of psilocybin for PPCS to inform whether there is any impact while addressing concerns regarding long-term effects of psilocybin use.

Content analysis of Reddit posts about coadministration of selective serotonin reuptake inhibitors and psilocybin mushrooms

RATIONALE

Treatments with the serotonergic psychedelic psilocybin are being investigated for multiple neuropsychiatric disorders. Because many patients with these disorders use selective serotonin reuptake inhibitors (SSRIs), understanding interactions between psilocybin and SSRIs is critical for evaluating the safety, efficacy, and scalability of psilocybin-based treatments. Current knowledge about these interactions is limited, as most clinical psilocybin research has prohibited concomittant SSRI use.

OBJECTIVES

We aimed to explore potential interactions between psilocybin and SSRIs by characterizing peoples' real-world experiences using psilocybin mushrooms and SSRIs together.

METHODS

We conducted a systematic search of Reddit for posts describing psilocybin mushroom and SSRI coadministration. We identified 443 eligible posts and applied qualitative content analysis to each.

RESULTS

8% of posts reported negative physical or psychological effects resulting from coadministration. These included 13 reports that may reflect serotonin toxicity, and 1 concerning for a psychotic/manic episode. 54% of posts described reduced intensity of the acute psilocybin experience, but 39% reported unchanged intensity with SSRI coadministration.

CONCLUSIONS

Psilocybin's interactions with SSRIs are likely complex and may depend on multiple factors. Prospective studies are needed to evaluate whether psilocybin treatments are reliably safe and effective in the setting of SSRI use.

The Tolerability and Safety of Psilocybin in Psychiatric and Substance-Dependence Conditions: A Systematic Review

OBJECTIVE

The objective of this systematic review is to determine the tolerability and safety of psilocybin in a variety of psychiatric and substance-dependence conditions.

DATA SOURCES

A systematic review was conducted using Embase, PubMed, Cochrane Central, and Web of Science through September 2023 using the following terminology: "psilocybin" AND "mental-disease" OR "substance-dependence" AND "disease-therapy," in addition to other synonymous key words.

STUDY SELECTION AND DATA EXTRACTION

Literature reporting acute effects and safety data following the use of psilocybin as the pharmacologic intervention in a clinical trial in adult patients with a psychiatric or substance-dependence condition were included. Following the application of inclusion and exclusion criteria, 16 studies were ultimately included in this review.

DATA SYNTHESIS

The most common treatment-emergent adverse effects reported were transient nausea and headache. Transient anxiety was reported as a frequent psychiatric effect, and 3 participants received a benzodiazepine for refractory anxiety during the psilocybin session. Psilocybin demonstrated modest increases in blood pressure and heart rate, and 1 participant received an antihypertensive for sustained hypertension during the psilocybin session. No cases of psilocybin-induced psychosis or Hallucinogen Persisting Perception Disorder were reported.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Treatment resistance remains a concern for psychiatric patients and novel therapies are needed to help alleviate the burden of morbidity and mortality. Psilocybin demonstrates promising acute and long-term safety that may allow for its use in psychiatric or substance-dependence conditions as an alternative to standards of care or in treatment-resistant patients.

CONCLUSIONS

Psilocybin has demonstrated tolerability and safety in recent literature that has investigated its therapeutic potential in a variety of psychiatric or substance-dependence conditions.

Ethnoracial inclusion in clinical trials of psychedelics: a systematic review

Background

Prior data indicate limited ethnoracial diversity in studies testing psychedelic-assisted treatments. Regulatory approval for psychedelic treatments may be imminent given growing evidence for safety and efficacy in a variety of psychiatric conditions. Data on racial and ethnic inclusion rates in clinical psychedelic studies since 2018 have not been systematically reported to date. With the publication of multiple new studies in the field, an update to existing ethnoracial inclusion data is needed to inform the state of the science and future directions for research.

Methods

Systematic review of Pubmed/MEDLINE, EMBASE, and Web of Science for studies of any design testing a psychedelic treatment for a psychiatric or substance use disorder published between January 1, 1994 and May 24, 2024. Search terms related to serotonergic psychedelics and MDMA, psychedelic therapies, psychiatric disorders, and substance use disorders were used. References of reviewed studies were screened for inclusion. Studies were rated for quality on a five-point scale ranging from 1 (most rigorous, i.e., properly powered randomized clinical trial) to 5 (least rigorous, e.g., case reports). Separate analyses were performed for two groups of studies, one involving all included studies meeting search criteria, and the other involving only studies from the USA. Rates of inclusion of different ethnoracial groups were calculated between studies published before and after December 31, 2017. Additionally, the proportion of White vs. non-White participants was compared between studies published before and after December 31, 2017. Finally, a nonparametric Mann-Whitney U test was used to compare the relative quality ratings of studies published before and after December 31, 2017.

Findings

787 studies were screened, and 39 studies were included. This included 16 studies (n = 282) from a prior review published in 2018 with an additional 23 studies (n = 1111) that were published after 2017, consisting of 14 randomized controlled studies, 8 open-label studies, and 1 placebo-controlled, within-subject, fixed-order study. In all included studies published after 2017, 85.6% of participants identified as non-Hispanic White, 3.1% as Black, 6.8% as Latinx/Hispanic, 3.6% as Asian, 1.2% as Indigenous, 3.5% as mixed race, 1.4% as other, Pooled data from all included studies (n = 1393) found 85.0% of participants identified as non-Hispanic White, 2.9% as Black, 5.9% as Latinx/Hispanic, 3.2% as Asian, 1.9% as Indigenous, 3.7% as mixed race, 1.4% as other. In studies conducted in the USA (n = 1074), 908 (84.5%) of participants identified as White, 36 (3.4%) as Black, 80 (7.4%) as Latinx/Hispanic, 43 (4.0%) as Asian, 15 (1.4%) as Indigenous, 40 (3.7%) as Mixed, and 9 (0.8%) as Other. Differences in inclusion rates were found when comparing studies published before and after December 31, 2017 for all included studies and all studies conducted in the USA. The proportion of White to non-White participants was found to have decreased in studies conducted in the USA over the same period, but not for all included studies.

Interpretation

Underrepresentation of ethnoracial minoritized populations persists in studies examining psychedelic therapies, despite growing calls for diversity. Non-Hispanic White participants remain an over-represented majority by a large margin, though, there were greater proportions of ethnic minoritized populations included in studies since 2018, particularly in studies conducted in the USA. This indicates progress towards equity in psychedelic research, though much work is needed to inform the safety and efficacy of psychedelic treatments in the general population.

Funding

There was no funding source for this study.

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.

Significant Psychedelic Experiences Evaluated for Mystical Characteristics Associated with Cannabis Use Reduction and Psychological Flexibility Improvement: A Naturalistic Cross-Sectional Retrospective Survey

Treating cannabis use disorder remains a significant challenge in the field of addiction medicine. Some recent studies point to psychedelic-assisted psychotherapy as a potential treatment option for substance use disorders. The objective of this study was therefore to explore the impact of naturalistic psychedelic experiences on cannabis use and psychological flexibility. An online retrospective survey was carried out on 152 cannabis users who also reported a significant experience induced by psychedelics in the past. Following a psychedelic experience, there was a significant and sustained reduction of average CUDIT score (p < .001), frequency of cannabis use (p < .001), and acute duration of daily intoxication (p < .001). Cannabis use reduction during the first month post-experience was significantly associated with the intensity of the mystical experience (p = .01). Participants reported a concomitant increased lasting improvement of psychological flexibility following the experience (p < .001), which was correlated to the intensity of the mystical experience during the first month post-experience (p = .04). This study demonstrates that naturalistic psychedelic experiences may be followed by a decrease in cannabis use. Positive health outcomes appear potentially connected to the intensity of the mystical experience, as well as an improvement in psychological flexibility.

A rapid narrative review of the clinical evolution of psychedelic treatment in clinical trials

Pre-prohibition psychedelic research with complex psychiatric patients generated a wealth of treatment methodologies and practices, providing invaluable clinical insights pertaining to the medical administration of psychedelics in various mental health diagnoses. Building upon these early studies, which lack the rigor and research tools available today, contemporary psychedelic research has focused on investigating the safety and efficacy of psychedelics in randomized controlled trials via psychometric measures and symptom assessments. Both then and now, the treatment context and the role of clinicians in psychedelic treatment has been recognized as an essential feature for positive patient outcomes. To broaden the knowledge base of modern psychedelic research and support the training of clinicians conducting medically supervised psychedelic research studies, this paper provides a review of pre-prohibition clinical research narratives pertaining to the phenomenology of psychedelic treatment and the role of the non-pharmacological treatment factors in the patient experience. Lastly, this paper explores a range of clinician perspectives and psychological interventions employed in pre-prohibition psychedelic research to inform future research directions and best practice guidelines.

Dynamic Functional Hyperconnectivity After Psilocybin Intake Is Primarily Associated With Oceanic Boundlessness

BACKGROUND

Psilocybin is a widely studied psychedelic substance that leads to the psychedelic state, a specific altered state of consciousness. To date, the relationship between the psychedelic state's neurobiological and experiential patterns remains undercharacterized because they are often analyzed separately. We investigated the relationship between neurobiological and experiential patterns after psilocybin by focusing on the link between dynamic cerebral connectivity and retrospective questionnaire assessment.

METHODS

Healthy participants were randomized to receive either psilocybin (n = 22) or placebo (n = 27) and scanned for 6 minutes in an eyes-open resting state during the peak subjective drug effect (102 minutes posttreatment) in ultrahigh field 7T magnetic resonance imaging. The 5-Dimensional Altered States of Consciousness Rating Scale was administered 360 minutes after drug intake.

RESULTS

Under psilocybin, there were alterations across all dimensions of the 5-Dimensional Altered States of Consciousness Rating Scale and widespread increases in averaged brain functional connectivity. Time-varying functional connectivity analysis unveiled a recurrent hyperconnected pattern characterized by low blood oxygen level-dependent signal amplitude, suggesting heightened cortical arousal. In terms of neuroexperiential links, canonical correlation analysis showed higher transition probabilities to the hyperconnected pattern with feelings of oceanic boundlessness and secondly with visionary restructuralization.

CONCLUSIONS

Psilocybin generates profound alterations at both the brain and the experiential levels. We suggest that the brain's tendency to enter a hyperconnected-hyperarousal pattern under psilocybin represents the potential to entertain variant mental associations. These findings illuminate the intricate interplay between brain dynamics and subjective experience under psilocybin, thereby providing insights into the neurophysiology and neuroexperiential qualities of the psychedelic state.

At the Forefront: Social Workers' Role in Psilocybin Treatment for Depression and Substance Misuse

This article underscores the critical role of social workers in harnessing the potential therapeutic benefits of psilocybin for treating major depressive disorder (MDD) and substance use disorder (SUD). Contemporary treatments for MDD often have side effects, and the success rate for SUD treatments remains low. The pervasiveness of MDD, combined with the challenges in treating SUD, highlights a need for innovative treatments. This article provides an overview of the resurgence of literature over the past two decades that illuminates the therapeutic promise of psilocybin for mental health treatment; clinical trials elucidate the efficacy of psilocybin-assisted therapy in mitigating MDD and demonstrate great promise in reducing SUD symptoms. The long-lasting posttreatment effect emphasizes its potential as a novel treatment modality. Furthermore, psilocybin's recognition as a "breakthrough therapy" by the U.S. Food and Drug Administration (FDA) and the accelerating pace of psychedelic reform bills indicate growing acceptance and interest in its therapeutic capacities. Psilocybin-assisted therapy emerges as a potent treatment option, showcasing remarkable effectiveness even after a single dose. Recommendations and pathways for social workers to be involved in psilocybin-assisted therapy investigation, advocacy, and implementation are provided.

[Psilocybin-Assisted Treatment of Depression, Anxiety and Substance use Disorders: Neurobiological Basis and Clinical Application]

Successful therapy of mental disorders is very important in view of the high level of suffering of those affected. Since established pharmaceutical and psychotherapeutic approaches do not lead to the desired improvement in all cases, complementary or alternative treatment methods are intensively researched. Psilocybin-assisted psychotherapy seems particularly promising, and has been approved in the USA for larger clinical trials. Psilocybin belongs to the group of psychedelics and influences psychological experiences. In assisted therapy, psilocybin is administered in controlled doses under medical supervision to patients with different mental disorders. In the studies conducted so far, longer-term positive effects could be shown after just one or a few doses. In order to provide a better understanding of the potential therapeutic mechanisms, this article will first describe neurobiological and psychological effects of psilocybin. To better assess the potential of psilocybin-assisted psychotherapy for various disorders, clinical studies conducted so far with patients administered psilocybin are reviewed.

A Critical View on New and Future Antidepressants

For the first time after many decades, many new antidepressants have been approved and many more are under various stages of development and will soon be available in the market. The new drugs present a range of new mechanisms of action with benefits in terms of speed of action, tolerability and range of treatable disorders. Neurosteroids have been recently approved and their rapid benefit may extend from postpartum depression to anxious depression and bipolar depression, dextromethorphan and bupropion combination may prove useful in major depression but also in treatment resistant depression, dextromethadone is a possible augmentation in partial antidepressant response, psychedelic drugs have the potential of long lasting benefits after a single administration, though are still experimental treatments. Botulinum has the same advantage of psychedelics of a single administration and its antidepressant effects may last for weeks or more. Further potentially interesting new antidepressant mechanisms include new drug targets, drug repurposing and genetic or epigenetic manipulations. It is therefore important that clinicians are kept up to date with new evidence so that new evidence can be rapidly translated into clinical practice.

Activity of prefrontal cortex serotonin 2A receptor expressing neurons is necessary for the head-twitch response of mice to psychedelic drug DOI in a sex-dependent manner

Serotonin 2A receptors (5-HT 2A Rs) mediate the effects of psychedelic drugs. 5-HT 2A R agonists, such as (-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI), that produce a psychedelic experience in humans induce a head-twitch response (HTR) behavior in rodents. However, it is unknown whether the activity of 5-HT 2A R expressing neurons is sufficient to produce the HTR in the absence of an agonist, or in which brain region 5-HT 2A Rs control the HTR. Here, we use an optogenetic approach to examine whether activation of 5-HT 2A R expressing neurons in the mouse prefrontal cortex (PFC) is sufficient to induce HTRs alone, or may augment the HTR produced by DOI, and if inhibition of these neurons prevents DOI-induced HTRs in mice. We crossed Htr2a -Cre mice to Cre-dependent optogenetic lines Ai32 (channelrhodopsin) and Ai39 (halorhodopsin) to selectively activate and inhibit (respectively) 5-HT 2A R-expressing neurons in the PFC of adult mice. We found that optogenetic stimulation of PFC 5-HT 2A R expressing neurons in the absence of an agonist does not increase HTRs in mice. In both male and female Ai32 mice that received vehicle, there was no difference in HTRs in mice that expressed Htr2a -Cre compared with control mice, indicating that optogenetic activation of 5-HT 2A R+ cells in the PFC was not sufficient to produce HTRs in the absence of an agonist. In female mice, activation of PFC 5-HT 2A R expressing neurons augmented the HTR produced by DOI. However, this result was not seen in male mice. In contrast, inhibition of 5-HT 2A R expressing neurons in the PFC prevented the increase in HTR produced by DOI in male, but not in female, mice. Together, these findings suggest that activation of 5-HT 2A Rs in the PFC is not sufficient to induce HTRs in the absence of a 5-HT 2A R agonist but is necessary for induction of HTRs by a 5-HT 2A R agonist in a sex-dependent manner.

Disentangling the acute subjective effects of classic psychedelics from their enduring therapeutic properties

Recent research with classic psychedelics suggests significant therapeutic potential, particularly for neuropsychiatric disorders. A mediating influence behind symptom resolution is thought to be the personal insight - at times, bordering on the mystical - one acquires during the acute phase of a psychedelic session. Indeed, current clinical trials have found strong correlations between the acute subjective effects (ASE) under the influence of psychedelics and their enduring therapeutic properties. However, with potential barriers to widespread clinical implementation, including the healthcare resource-intensive nature of psychedelic sessions and the exclusion of certain at-risk patient groups, there is an active search to determine whether ASE elimination can be accompanied by the retention of persisting therapeutic benefits of these class of compounds. Recognizing the aberrant underlying neural circuitry that characterizes a range of neuropsychiatric disorders, and that classic psychedelics promote neuroplastic changes that may correct abnormal circuitry, investigators are rushing to design and discover compounds with psychoplastogenic, but not hallucinogenic (i.e., ASE), therapeutic potential. These efforts have paved the discovery of 'non-psychedelic/subjective psychedelics', or compounds that lack hallucinogenic activity but with therapeutic efficacy in preclinical models. This review aims to distill the current evidence - both clinical and preclinical - surrounding the question: can the ASE of classic psychedelics be dissociated from their sustained therapeutic properties? Several plausible clinical scenarios are then proposed to offer clarity on and potentially answer this question.

Serotonergic Psychedelics: A Comparative Review of Efficacy, Safety, Pharmacokinetics, and Binding Profile

Psychedelic compounds, including psilocybin, LSD (lysergic acid diethylamide), DMT (N,N -dimethyltryptamine), and 5-MeO-DMT (5-methoxy-N,N-dimethyltryptamine), all of which are serotonin 2A receptor agonists, are being investigated as potential treatments. This review aims to summarize the current clinical research on these 4 compounds and mescaline to guide future research. Their mechanism(s) of action, pharmacokinetics, pharmacodynamics, efficacy, and safety were reviewed. While evidence for therapeutic indications, with the exception of psilocybin for depression, is still relatively scarce, we noted no differences in psychedelic effects beyond effect duration. Therefore, it remains unclear whether different receptor profiles contribute to the therapeutic potential of these compounds. More research is needed to differentiate these compounds in order to inform which compounds might be best for different therapeutic uses.

Efficacy and safety of psychedelics for the treatment of mental disorders: A systematic review and meta-analysis

We aim to systematically review and meta-analyze the effectiveness and safety of psychedelics [psilocybin, ayahuasca (active component DMT), LSD and MDMA] in treating symptoms of various mental disorders. Web of Science, Embase, EBSCO, and PubMed were searched up to February 2024 and 126 articles were finally included. Results showed that psilocybin has the largest number of articles on treating mood disorders (N = 28), followed by ayahuasca (N = 7) and LSD (N = 6). Overall, psychedelics have therapeutic effects on mental disorders such as depression and anxiety. Specifically, psilocybin (Hedges' g = -1.49, 95% CI [-1.67, -1.30]) showed the strongest therapeutic effect among four psychedelics, followed by ayahuasca (Hedges' g = -1.34, 95% CI [-1.86, -0.82]), MDMA (Hedges' g = -0.83, 95% CI [-1.33, -0.32]), and LSD (Hedges' g = -0.65, 95% CI [-1.03, -0.27]). A small amount of evidence also supports psychedelics improving tobacco addiction, eating disorders, sleep disorders, borderline personality disorder, obsessive-compulsive disorder, and body dysmorphic disorder. The most common adverse event with psychedelics was headache. Nearly a third of the articles reported that no participants reported lasting adverse effects. Our analyses suggest that psychedelics reduce negative mood, and have potential efficacy in other mental disorders, such as substance-use disorders and PTSD.

Therapeutic potential of psychedelics: History, advancements, and unexplored frontiers

Psychedelics (serotonergic hallucinogens) are psychoactive substances that can alter perception and mood, and affect cognitive functions. These substances activate 5-HT2A receptors and may exert therapeutic effects. Some of the disorders for which psychedelic-assisted therapy have been studied include depression, addiction, anxiety and post-traumatic stress disorder. Despite the increasing number of studies reporting clinical effectiveness, with fewer negative symptoms and, additionally, minimal side effects, questions remain to be explored in the field of psychedelic medicine. Although progress has been achieved, there is still little understanding of the relationship among human brain and the modulation induced by these drugs. The present article aimed to describe, review and highlight the most promising findings in the literature regarding the (putative) therapeutic effects of psychedelics.

From taboo to treatment: The emergence of psychedelics in the management of pain and opioid use disorder

The rise of psychedelics in contemporary medicine has sparked interest in their potential therapeutic applications. While traditionally associated with countercultural movements and recreational use, recent research has shed light on the potential benefits of psychedelics in various mental health conditions. In this review, we explore the possible role of psychedelics in the management of chronic pain and opioid use disorder (OUD), 2 critical areas in need of innovative treatment options. Pain control remains a significant clinical challenge, particularly for individuals with OUD and those who receive long-term opioid therapy who develop marked tolerance to opioid-induced analgesia. Despite the magnitude of this problem, there is a scarcity of controlled studies investigating pain management alternatives for these populations. Drawing from preclinical and human evidence, we highlight the potential of psychedelics to act on shared neurobiological substrates of chronic pain and OUD, potentially reversing pain- and opioid-induced neuroadaptations, such as central sensitization. We elaborate on the multifaceted dimensions of the pain experience (sensory, affective and cognitive) and their intersections that overlap with opioid-related phenomena (opioid craving and withdrawal), hypothesizing how these processes can be modulated by psychedelics. After summarizing the available clinical research, we propose mechanistic insights and methodological considerations for the design of future translational studies and clinical trials, building on a shared clinical and neurobiological understanding of chronic pain and OUD. Our intention is to provide timely perspectives that accelerate the development and exploration of novel therapeutics for chronic pain and OUD amidst the escalating opioid crisis.

Deciphering psilocybin: Cytotoxicity, anti-inflammatory effects, and mechanistic insights

A decade of clinical research has indicated psilocybin's effectiveness in treating various neuropsychiatric disorders, such as depression and substance abuse. The correlation between increased pro-inflammatory cytokines and the severity of neuropsychiatric symptoms, along with the known anti-inflammatory potential of some psychedelics, suggests an immunomodulatory role for psilocybin. This study aims to understand the mechanism of action of psilocybin by investigating the cytotoxic and immunomodulatory effects of psilocybin and psilocin on both resting and LPS-activated RAW 264.7 murine macrophages. The study evaluated the cytotoxicity of psilocybin and psilocin using an LDH assay across various doses and assessed their impact on cytokine production in RAW 264.7 cells, measuring cytokine expression via ELISA. Different doses, including those above and below the LC50, were used in both pre-treatment and post-treatment approaches. The LDH assay revealed that psilocybin is almost twice as cytotoxic as psilocin, with an LC50 of 12 ng/ml and 28 ng/ml, respectively. In resting macrophages, both psilocybin and psilocin triggered significant release of TNF- α after 4 h, with the lowest doses inducing higher levels of the cytokine than the highest doses. IL-10 expression in resting cells was only triggered by the highest dose of psilocin in the 4-hour incubation group. In LPS-stimulated cells, psilocin reduced TNF- α levels more than psilocybin in pre-treatment and post-treatment, with no significant effects on IL-10 in pre-treatment. Psilocin, but not psilocybin, induced a significant increase of IL-10 in post-treatment, leading to the conclusion that psilocin, but not psilocybin, exerts anti-inflammatory effects on classically activated macrophages.

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.

The therapeutic alliance between study participants and intervention facilitators is associated with acute effects and clinical outcomes in a psilocybin-assisted therapy trial for major depressive disorder

We examined if the therapeutic alliance between study participants and intervention facilitators in a psilocybin-assisted therapy (PAT) trial changed over time and whether there were relationships between alliance, acute psilocybin experiences, and depression outcomes. In a randomized, waiting list-controlled clinical trial for major depressive disorder in adults (N = 24), participants were randomized to an immediate (N = 13) or delayed (N = 11) condition with two oral doses of psilocybin (20mg/70kg and 30mg/70kg). Ratings of therapeutic alliance significantly increased from the final preparation session to one-week post-intervention (p = .03, d = .43). A stronger total alliance at the final preparation session predicted depression scores at 4 weeks (r = -.65, p = .002), 6 months (r = -.47, p = .036), and 12 months (r = -.54, p = .014) post-intervention. A stronger total alliance in the final preparation session was correlated with higher peak ratings of mystical experiences (r = .49, p = .027) and psychological insight (r = .52, p = .040), and peak ratings of mystical experience and psychological insight were correlated with depression scores at 4 weeks (r = -.45, p = .030 for mystical; r = -.75, p < .001 for insight). Stronger total alliance one week after the final psilocybin session predicted depression scores at 4 weeks (r = -.85, p < .001), 3 months (r = -.52, p = .010), 6 months (r = -.77, p < .001), and 12 months (r = -.61, p = .001) post-intervention. These findings highlight the importance of the therapeutic relationship in PAT. Future research should explore therapist and participant characteristics which maximize the therapeutic alliance and evaluate its relationship to treatment outcomes. Trial registration: Registration: Clinicaltrials.gov NCT03181529. https://classic.clinicaltrials.gov/ct2/show/NCT03181529.

The mechanistic divide in psychedelic neuroscience: An unbridgeable gap?

In recent years, psychedelics have generated considerable excitement and interest as potential novel therapeutics for an array of conditions, with the most advanced evidence base in the treatment of certain severe and/or treatment-resistant psychiatric disorders. An array of clinical and pre-clinical evidence has informed our current understanding of how psychedelics produce profound alterations in consciousness. Mechanisms of psychedelic action include receptor binding and downstream cellular and transcriptional pathways, with long-term impacts on brain structure and function-from the level of single neurons to large-scale circuits. In this perspective, we first briefly review and synthesize separate lines of research on potential mechanistic processes underlying the acute and long-term effects of psychedelic compounds, with a particular emphasis on highlighting current theoretical models of psychedelic drug action and their relationships to therapeutic benefits for psychiatric and brain-based disorders. We then highlight an existing area of ongoing controversy we argue is directly informed by theoretical models originating from disparate levels of inquiry, and we ultimately converge on the notion that bridging the current chasm in explanatory models of psychedelic drug action across levels of inquiry (molecular, cellular, circuit, and psychological/behavioral) through innovative methods and collaborative efforts will ultimately yield the comprehensive understanding needed to fully capitalize on the potential therapeutic properties of these compounds.

Cloning, characterization and specificity of a new aromatic-L-amino-acid decarboxylases from Bufo bufo gargarizans

5-Hydroxytryptamine (5-HT) and its derivative bufotenine, which possess important physiological functions, are the primary active components in the secretions of toad parotid and skin gland. However, the biosynthetic pathway of these substances remains unclear in toads. To characterize toad's Aromatic-L-amino-acid decarboxylase (AADC), the key enzyme in the predicted 5-HT derivatives biosynthetic pathway, the full-length cDNA of AADC from Bufo bufo gargarizans (BbgAADC) was cloned from the parotoid gland of B. bufo gargarizans. The recombinant BbgAADC exhibited optimal expression in E. coli BL21 (DE3) containing pCold-BbgAADC after induction for 16 h at 15 °C with 0.3 mM IPTG, resulting in substantial yields of soluble proteins. The enzymological properties of BbgAADC were assessed, and it was determined that the optimal reaction temperature was 37 °C, the optimal pH was 8.6, and the optimum molar ratio of pyridoxal-5'-phosphate (PLP) to BbgAADC was found to be 3.6:1. Additionally, high substrate specificity was observed, as BbgAADC could catalyze the production of 5-HT from 5-hydroxytryptophan (5-HTP) but not dopamine or tryptamine from levodopa or tryptophan, respectively. The Km of the recombinant protein BbgAADC was 0.2918 mM and the maximum reaction rate (Vmax) was 1.182 μM·min-1 when 5-HTP was used as substrate. The Kcat was 0.0545 min-1, and Kcat/Km was 0.1868 mM-1·min-1. To elucidate the mechanism of BbgAADC, molecular docking was performed with PLP and 5-HTP, or the external aldimine formed by 5-HTP and PLP. The results indicated that the active sites for BbgAADC to bind with PLP were K303, H192, N300, A148, F309, T246, A273, and T147. W71, Y79, F80, P81, T82, H192, T246, N300, H302, F309, and R477 served as catalytically active sites for the binding of BbgAADC to 5-HTP. Furthermore, R447, W71, S149, N300, A148, and T147 of BbgAADC were involved in the decarboxylation reaction of the aldimine formed by PLP and 5-HTP.

Psychedelic Therapy: A Primer for Primary Care Clinicians-Psilocybin

BACKGROUND

The primary psychoactive drug in magic mushrooms, psilocybin, induces profound alterations in consciousness through the 5-HT2A receptor. This review consolidates current research findings to elucidate the pharmacology, safety profile, and clinical applications of psilocybin.

AREAS OF UNCERTAINTY

Despite initial concerns that psilocybin could cause psychosis, contemporary research has demonstrated that psilocybin is generally safe. The most common adverse effects are nausea and headache, yet both tend to be transient. Serious adverse events can generally be avoided in controlled settings such as clinical trials. However, in the largest clinical trial to date, there were a total of 7 reported cases of suicidal ideation, up to 12 weeks after receiving a single 25 mg dose of psilocybin. That being said, all 7 cases did not respond to the treatment. Although selective serotonin reuptake inhibitors may blunt the hallucinogenic qualities of psilocybin, preliminary research suggests that they may enhance its antidepressant effects.

THERAPEUTIC ADVANCES

In clinical trials, psilocybin has shown promise for treating major depressive disorder and treatment-resistant depression. Initial studies indicated that 42%-57% of patients underwent remission after psilocybin-assisted therapy, which suggests that psilocybin is more effective than existing antidepressant medications. Clinical data have also demonstrated that psilocybin can manage substance use disorders and end-of-life anxiety with clinical outcomes that are sustained for months and sometimes years after 1 or 2 doses.

LIMITATIONS

However, larger Phase II trials with more than 100 depressed participants have shown a much smaller remission rate of 25%-29%, though these studies still observed that psilocybin causes a significant reduction in depressive symptoms.

CONCLUSIONS

Aside from ketamine, psilocybin is the most clinically well-researched psychedelic drug, with trials that have enrolled hundreds of participants and multiple therapeutic applications. Phase III trials will determine whether psilocybin lives up to the promise that it showed in previous clinical trials.

Psychedelic Therapy: A Primer for Primary Care Clinicians-Historical Perspective and Overview

BACKGROUND

Psychedelic drugs have recently emerged as plausibly effective pharmacological agents for the management of depression, anxiety, and other neuropsychiatric conditions, including those that are treatment-resistent. The latter half of the 20th century marked a revolution in the treatment of mental illnesses, exemplified by the introduction of selective serotonin reuptake inhibitors and other pharmacological agents. Nevertheless, mental illness remains a major public health crisis, affecting nearly one billion individuals worldwide.

AREAS OF UNCERTAINTY

Because of the decades-long status of several psychedelics as Schedule I drugs, there have not been very many large, double-blind, randomized controlled trials of psychedelics. Owing to small sample sizes, there may be rare yet serious adverse events that have not been reported in the clinical trials thus far.

THERAPEUTIC ADVANCES

Esketamine, a dissociative hallucinogen drug, was approved for the management of major depressive disorder by the Food and Drug Administration in 2019. As of January 2024, two Phase III trials of 3,4-methylenedioxymethamphetamine (MDMA), a synthetic drug that inhibits the serotonin transporter, have been completed; the results indicate that MDMA is superior to existing pharmacological treatments for post-traumatic stress disorder. A phase III trial of psilocybin, a naturally occurring serotonin receptor partial agonist, is currently underway. The following series details the current state of research in psychedelic therapeutics, including lysergic acid diethylamide (LSD), N-N-dimethyltryptamine (DMT) and ayahuasca, psilocybin, ibogaine, MDMA, and ketamine.

LIMITATIONS

While initial clinical trials of psychedelics for depression were very promising, trials of psilocybin with larger sample sizes (100+ participants) suggest that its remission rate is 25%-29%. This is about the same as the remission rate of antidepressants, which is roughly 30% according to the landmark STAR*D trial.

CONCLUSIONS

Psychedelic drugs and structural derivatives offer a great deal of promise for the management of a wide range of psychiatric morbidities. It is imperative that clinicians become familiar with these novel agents and learn how to integrate psychedelic therapy with the rest of their care through open communication and referral.

Who are you after psychedelics? A systematic review and a meta-analysis of the magnitude of long-term effects of serotonergic psychedelics on cognition/creativity, emotional processing and personality

This systematic review and a meta-analysis synthesised the results from contemporary, randomized and non-randomized controlled studies to assess lasting (one week minimum) changes on cognition/creativity, emotional processing and personality from serotonergic psychedelics. PubMed, Embase and PsycInfo were searched in July 2022. Risk of bias was assessed using Rob 2.0 and ROBINS-I. Ten studies met the eligibility criteria which involved 304 participants. No statistically significant effects were found for the majority outcome measures across the three constructs. A meta-analysis of emotional recognition outcomes found an overall significant effect for faster reaction times in the active treatment groups for disgust (SMD=-0.63, 95% CI=[-1.01 to -0.25], I2 = 65%) and sadness (SMD=-0.45, 95% CI=[-0.85 to -0.06], I2 = 60%). Future research should include larger samples, better control conditions, standardized doses and longer follow-up periods to confirm these preliminary findings.

Psychedelic substitution: altered substance use patterns following psychedelic use in a global survey

Introduction

Recent research suggests that psychedelics may have potential for the treatment of various substance use disorders. However, most studies to date have been limited by small sample sizes and neglecting to include non-North American and European populations.

Methods

We conducted a global, cross-sectional online survey of adults (n = 5,268, 47.2% women) self-reporting past or current psychedelic use and investigated whether psychedelic use was associated with changes in use of other substances.

Results

Nearly three-quarters (70.9%; n = 3,737/5,268) reported ceasing or decreasing use of one or more non-psychedelic substances after naturalistic psychedelic use. Among those with previous use, 60.6% (n = 2,634/4,344) decreased alcohol use, 55.7% (n = 1,223/2,197) decreased antidepressant use, and 54.2% (n = 767/1,415) decreased use of cocaine/crack. Over a quarter of the sample indicated that their decrease in substance use persisted for 26 weeks or more following use of a psychedelic. Factors associated with decreased use included a motivation to either decrease one's substance use or self-treat a medical condition. Importantly, 19.8% of respondents also reported increased or initiated use of one or more other substances after psychedelic use, with illicit opioids (14.7%; n = 86/584) and cannabis (13.3%; n = 540/4,064) having the highest proportions. Factors associated with increased substance use included having a higher income and residing in Canada or the US.

Discussion

Although limited by cross-sectional study design, this large observational study will help inform future studies aiming to investigate the relationship between substance use patterns and psychedelic use.