Lysergic Acid Diethylamide-Assisted Therapy in Patients With Anxiety With and Without a Life-Threatening Illness: A Randomized, Double-Blind, Placebo-Controlled Phase II Study

The association between study design and antidepressant effects in psychedelic-assisted therapy: A meta-analysis

Different study designs of psychedelic trials may impact the blinding and expectance, leading to biased treatment effects. This study aimed to examine the association between antidepressant efficacy and study designs in psychedelic trials. Six databases were systematically searched. Eligible trials were required to investigate the efficacy of psychedelics (psilocybin, lysergic acid diethylamide [LSD], 3,4-Methylenedioxymethamphetamine [MDMA], and ayahuasca) in adult patients with depressive symptoms. We only considered oral psychedelic-assisted therapy without concomitant use of antidepressants. The primary outcome was the change in depressive symptoms. There were five study designs of psychedelic trials, including non-active-drug-as-placebo, active-drug-as-placebo, waitlist-as-control, fixed-order, and pre-post designs. In non-active-drug -as-placebo design, psilocybin (k = 4, Hedges' g [g] = 0.87, 95 % confidence intervals[CIs] = 0.58 to 1.16) and MDMA (k = 2, g = 0.65, 95%CIs = 0.26 to 1.05) were associated with large and medium effect sizes, respectively. In active-drug-as-placebo design, both psilocybin (k = 2, g = 0.71, 95%CIs = -0.01 to 1.43) and MDMA (k = 3, g = 0.53, 95%CIs = -0.23 to 1.28) were not statistically significant. In pre-post single-arm (k = 3, g = 2.51, 95%CIs = 1.00 to 4.02) and waitlist-as-control (k = 1, g = 2.88, 95%CIs = 1.75 to 4.00) designs, psilocybin showed a large effect size of antidepressant effect. Ayahuasca also showed a large effect size in both pre-post (k = 2, g = 1.88, 95%CIs = 1.18 to 2.57) and non-active-drug-as-placebo (k = 1, g = 1.60, 95%CIs = 0.84 to 2.36) designs. LSD was associated with a significant antidepressant effect only in non-active-drug-as-placebo design (k = 1, g = 1.49, 95%CIs = 0.80 to 2.17) but not in active-drug-as-placebo design (k = 1, g = 0.44, 95%CIs = -0.90 to 1.78). The antidepressant effects of psychedelics may be overestimated in studies with pre-post single-arm, non-active-drugs-as placebo, and waitlist-control designs. Restricted sample size, difficulty with establishing blinding for participants, and over expectancy limit the estimation of the antidepressant effect of psychedelic-assisted therapy.

Acute dose-dependent effects of mescaline in a double-blind placebo-controlled study in healthy subjects

Classic psychedelics have regained interest in research and therapy. Despite the long tradition of the human use of mescaline, modern data on its dose-dependent acute effects and pharmacokinetics are lacking. Additionally, its mechanism of action has not been investigated in humans. We used a randomized, double-blind, placebo-controlled, crossover design in 16 healthy subjects (8 women) who received placebo, mescaline (100, 200, 400, and 800 mg), and 800 mg mescaline together with the serotonin 5-hydroxytryptamine-2A (5-HT2A) receptor antagonist ketanserin (40 mg) to assess subjective effects, autonomic effects, adverse effects, and pharmacokinetics up to 30 h after drug administration. Mescaline at doses >100 mg induced dose-dependent acute subjective effects. Mescaline increased systolic and diastolic blood pressure at doses >100 mg, with no difference between doses of 200-800 mg. Heart rate increased dose-dependently. Pharmacokinetics of mescaline were dose-proportional. Maximal concentrations were reached after approximately 2 h, and the plasma elimination half-life was approximately 3.5 h. The average duration of subjective effects increased from 6.4 to 14 h with increasing doses of 100-800 mg mescaline. Nausea and emesis were frequent adverse effects at the 800 mg dose. Co-administration of ketanserin attenuated and shortened acute effects of 800 mg mescaline to become comparable to the 100 and 200 mg doses. There were no ceiling effects of the subjective response within the investigated dose range, but tolerability was lower at the highest doses. These results may assist with dose finding for future research and suggest that acute effects of mescaline are primarily mediated by 5-HT2A receptors.

Classical psychedelics' action on brain monoaminergic systems

The study of the mechanism of action of classical psychedelics has gained significant interest due to their clinical potential in the treatment of several psychiatric conditions, including major depressive and anxiety disorders. These drugs bind 5-hydroxytryptamine receptors (5-HTR) including 5-HT1AR, 5-HT2AR, 5-HT2BR, and/or 5-HT2CR, as well as other targets. 5-HTRs regulate the activity of ascending monoaminergic neurons, a mechanism primarily involved in the action of classical antidepressant drugs, antipsychotics, and drugs of abuse. Sparse neurochemical data have been produced on the control of monoaminergic neuron activity in response to classical psychedelics. Here we review the available data in order to determine whether classical psychedelics have specific neurochemical effects on serotonergic, dopaminergic, and noradrenergic neurons. The data show that these drugs have disparate effects on each monoaminergic system, demonstrating a complex response with state-dependent and region-specific effects. For instance, several psychedelics inhibit the firing of serotonergic neurons, although this is not necessarily associated with a decrease in serotonin release in all regions. Noradrenergic neuron spontaneous activity also appears to be inhibited by psychedelics, also not necessarily associated with a decrease in noradrenaline release in all regions. Psychedelics influence on dopaminergic systems is also complex as the above-mentioned 5-HTRs may have opposing effects on dopaminergic neuron activity, in a state-dependent manner. There is an apparent lack of clear neuronal signature induced by psychedelics on monoaminergic neuron activity despite specific recurrent mechanisms. This review provides a current summary of the action of psychedelics on monoamine neuromodulators serotonin, dopamine and noradrenaline, compiling reoccurring and contradictory findings demonstrating that a monoamine signature of psychedelics, if applicable, would be state- and region-dependant.

Chemical Reactivity Parameters to Analyze Psychedelics: How Do We Explain the Potency of the Drugs?

Psychedelics are psychoactive substances that produce changes in thoughts and feelings and modifications in perceptions of reality. The most potent psychedelic is also the first semisynthetic hallucinogen (lysergic acid diethylamide). Psychedelics have been investigated for decades because of their potential therapeutic effects in the treatment of neuropsychiatric diseases and also because these drugs are useful in controlling addictions to other substances. In this investigation, we analyze 27 psychedelic molecules. These compounds are serotonergic psychedelics; that is, they are serotonin agonists. We analyze the electron transfer properties to better understand the mechanism of action of these substances. We found that the electron acceptance capacity is related to the potency of the drugs: the best electron acceptor is also the most potent drug. We also used global softness as a parameter of reactivity. Molecules with greater global softness are more polarizable and also have greater potency. These results are useful to continue our understanding of the mechanism of action of psychotropic drugs.

Naturalistic psychedelic therapy: The role of relaxation and subjective drug effects in antidepressant response

BACKGROUND

Psychedelic-assisted therapy (PAT) is permitted in Switzerland under its limited medical use program. Data from patients in this program represent a unique opportunity to analyze the real-world practice of PAT.

AIMS

This study compared the subjective effects of lysergic acid diethylamide (LSD) and psilocybin between patients undergoing PAT and healthy volunteers. For the patients, it also investigated the relationship between antidepressant effects and six measures of acute drug effects.

METHODS

We compared data on acute psychedelic drug effects between 28 PAT patients with data from 28 healthy participants who participated in a randomized, double-blind crossover trial. All participants received varying doses of psilocybin and LSD. Subjective effects were assessed on an hourly basis during the acute drug effects, and the Mystical Experience Questionnaire (MEQ) was completed retrospectively. For patients, depressive symptoms were assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS).

RESULTS

Ratings of overall drug effect and mystical experience were similar across groups. Compared with healthy controls, patients reported lower ratings of ego dissolution. Patients showed a significant decrease in MADRS scores, and the greatest predictor of antidepressant outcome was relaxation during the PAT session. We did not observe a relationship between mystical-type experiences and antidepressant effects. Most patients experienced mild adverse effects which resolved within 48 h.

CONCLUSION

PAT reduced depressive symptoms in this heterogeneous patient group. Patients may experience more challenging psychedelic effects and reduced ego dissolution. Hourly assessment of drug effects may predict clinical outcomes better than retrospectively assessed mystical experiences, and the impact of relaxation during PAT should be investigated further.

Ventral hippocampal parvalbumin interneurons gate the acute anxiolytic action of the serotonergic psychedelic DOI

There has been a recent renewal of interest in the therapeutic potential of serotonergic psychedelics. Here, we uncover the essential role of ventral hippocampus (vHpc) GABAergic interneurons in the anxiolytic effect evoked by the serotonergic psychedelic 2,5-dimethoxy-4-iodoamphetamine (DOI). Integrating anatomical, pharmacological, and genetic approaches, we show that 5-HT2A receptors in the CA1/subiculum (CA1/sub) region of the vHpc are required for the anxiolytic action of DOI. In vivo electrophysiology and opto-tagging experiments indicate that DOI enhances the firing rate of hippocampal fast-spiking parvalbumin (PV)-positive interneurons, most of which express the 5-HT2A receptors. Restoration of 5-HT2A receptors in PV-positive interneurons in a loss-of-function background reinstated the anxiolytic responses evoked by DOI in the vHpc CA1/sub region. Collectively, our results localize the acute anxiolytic action of a serotonergic psychedelic to 5-HT2A receptors in the ventral hippocampus and specifically identify PV-positive fast-spiking cells as a cellular trigger for the psychedelic-induced relief of anxiety-like behavior.

Short-term safety and tolerability profile of 5-methoxy-N,N-dimethyltryptamine in human subjects: a systematic review of clinical trials

Introduction

Psychedelic agents have regained the attention of pharmaceutical companies as promising treatments for depressive episodes. 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT), an atypical psychedelic, is emerging as a potentially effective, novel rapid-acting antidepressant. In this systematic review, we analyze the safety and tolerability evidence from clinical trials.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, electronic databases (PubMed, SCOPUS, Web of Science, EMBASE, and EBSCO) were searched from inception until 15 May 2024 to identify clinical trials (regardless of phase) reporting on short-term safety and tolerability profile of 5-MeO-DMT using the following keywords in various combinations: 5-methoxy-N, N-dimethyltryptamine, 5-MeO-DMT, safety, adverse, adverse reaction, side effects, tolerability, dropout, healthy volunteer, healthy participant, depression, major depressive disorder. Only studies written in English were considered.

Results

Initial search yielded 100 records, out of which 3 met the inclusion criteria. These studies reported on the results from clinical trial phases I and I/II, with a total of 78 participants included; two studies involved healthy volunteers, and one included patients with treatment-resistant depression. Although the data is limited, it confirms a good short-term safety and tolerability profile for 5-MeO-DMT, with no serious adverse events (SAEs) reported. Furthermore, no drop-outs were reported.

Conclusion

5-MeO-DMT administration in human subjects presents favorable short-term safety and tolerability profile. Importantly, no SAEs have been documented, and no adverse events led to participant withdrawal from the studies There is a need for future randomized, double-blind, placebo-controlled trials with larger samples and follow-up to assess potential chronic adverse events.

Psychedelics and schizophrenia: a double-edged sword

Psychedelics have shown promising effects in several psychiatric diseases as demonstrated by multiple clinical trials. However, no clinical experiments on patients with schizophrenia have been conducted up to date, except for some old semi-anecdotal studies mainly performed in the time-span '50s-'60s. Notably, these studies reported interesting findings, particularly on the improvement of negative symptoms and social cognition. With no doubts the lack of modern clinical studies is due to the psychomimetic properties of psychedelics, a noteworthy downside that could worsen positive symptoms. However, a rapidly increasing body of evidence has suggested that the mechanisms of action of such compounds partially overlaps with the pathogenic underpinnings of schizophrenia but in an opposite way. These findings suggest that, despite being a controversial issue, the use of psychedelics in the treatment of schizophrenia would be based on a strong biological rationale. Therefore, the aim of our perspective paper is to provide a background on the old experiments with psychedelics performed on patients with schizophrenia, interpreting them in the light of recent molecular findings on their ability to induce neuroplasticity and modulate connectivity, the immune and TAARs systems, neurotransmitters, and neurotropic factors. No systematic approach was adopted in reviewing the evidence given the difficulty to retrieve and interpret old findings. Interestingly, we identified a therapeutic potential of psychedelics in schizophrenia adopting a critical point of view, particularly on negative symptoms and social cognition, and we summarized all the relevant findings. We also identified an eligible subpopulation of chronic patients predominantly burdened by negative symptoms, outlining possible therapeutic strategies which encompass very low doses of psychedelics (microdosing), carefully considering safety and feasibility, to pave the way to future clinical trials.

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.

Large-scale brain connectivity changes following the administration of lysergic acid diethylamide, d-amphetamine, and 3,4-methylenedioxyamphetamine

Psychedelics have recently attracted significant attention for their potential to mitigate symptoms associated with various psychiatric disorders. However, the precise neurobiological mechanisms responsible for these effects remain incompletely understood. A valuable approach to gaining insights into the specific mechanisms of action involves comparing psychedelics with substances that have partially overlapping neurophysiological effects, i.e., modulating the same neurotransmitter systems. Imaging data were obtained from the clinical trial NCT03019822, which explored the acute effects of lysergic acid diethylamide (LSD), d-amphetamine, and 3,4-methylenedioxymethamphetamine (MDMA) in 28 healthy volunteers. The clinical trial employed a double-blind, placebo-controlled, crossover design. Herein, various resting-state connectivity measures were examined, including within-network connectivity (integrity), between-network connectivity (segregation), seed-based connectivity of resting-state networks, and global connectivity. Differences between placebo and the active conditions were assessed using repeated-measures ANOVA, followed by post-hoc pairwise t-tests. Changes in voxel-wise seed-based connectivity were correlated with serotonin 2 A receptor density maps. Compared to placebo, all substances reduced integrity in several networks, indicating both common and unique effects. While LSD uniquely reduced integrity in the default-mode network (DMN), the amphetamines, in contrast to our expectations, reduced integrity in more networks than LSD. However, LSD exhibited more pronounced segregation effects, characterized solely by decreases, in contrast to the amphetamines, which also induced increases. Across all substances, seed-based connectivity mostly increased between networks, with LSD demonstrating more pronounced effects than both amphetamines. Finally, while all substances decreased global connectivity in visual areas, compared to placebo, LSD specifically increased global connectivity in the basal ganglia and thalamus. These findings advance our understanding of the distinctive neurobiological effects of psychedelics, prompting further exploration of their therapeutic potential.

Epigenetic mechanisms of rapid-acting antidepressants

BACKGROUND

Rapid-acting antidepressants (RAADs), including dissociative anesthetics, psychedelics, and empathogens, elicit rapid and sustained therapeutic improvements in psychiatric disorders by purportedly modulating neuroplasticity, neurotransmission, and immunity. These outcomes may be mediated by, or result in, an acute and/or sustained entrainment of epigenetic processes, which remodel chromatin structure and alter DNA accessibility to regulate gene expression.

METHODS

In this perspective, we present an overview of the known mechanisms, knowledge gaps, and future directions surrounding the epigenetic effects of RAADs, with a focus on the regulation of stress-responsive DNA and brain regions, and on the comparison with conventional antidepressants.

MAIN BODY

Preliminary correlative evidence indicates that administration of RAADs is accompanied by epigenetic effects which are similar to those elicited by conventional antidepressants. These include changes in DNA methylation, post-translational modifications of histones, and differential regulation of non-coding RNAs in stress-responsive chromatin areas involved in neurotrophism, neurotransmission, and immunomodulation, in stress-responsive brain regions. Whether these epigenetic changes causally contribute to the therapeutic effects of RAADs, are a consequence thereof, or are unrelated, remains unknown. Moreover, the potential cell type-specificity and mechanisms involved are yet to be fully elucidated. Candidate mechanisms include neuronal activity- and serotonin and Tropomyosine Receptor Kinase B (TRKB) signaling-mediated epigenetic changes, and direct interaction with DNA, histones, or chromatin remodeling complexes.

CONCLUSION

Correlative evidence suggests that epigenetic changes induced by RAADs accompany therapeutic and side effects, although causation, mechanisms, and cell type-specificity remain largely unknown. Addressing these research gaps may lead to the development of novel neuroepigenetics-based precision therapeutics.

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.

Adverse Events in Studies of Classic Psychedelics: A Systematic Review and Meta-Analysis

Importance

A clear and comprehensive understanding of risks associated with psychedelic-assisted therapy is necessary as investigators extend its application to new populations and indications.

Objective

To assess adverse events (AEs) associated with classic psychedelics, particularly serious AEs (SAEs) and nonserious AEs (NSAEs) requiring medical or psychiatric evaluation.

Data Sources

The search for potentially eligible studies was conducted in the Scopus, MEDLINE, PsycINFO, and Web of Science databases from inception through February 8, 2024.

Study Selection

Two independent reviewers screened articles of classic psychedelics (lysergic acid diethylamide [LSD], psilocybin, dimethyltryptamine [DMT], and 5-methoxy-N,N-dimethyltryptamine [5-MeO-DMT]) involving administration in clinical or research contexts.

Data Extraction and Synthesis

AE data were extracted and synthesized by 2 reviewers and were used for random-effects meta-analysis of AE frequency and heterogeneity. Risk of bias assessment focused on AE ascertainment (eg, systematic assessment and quality of follow-up).

Main Outcomes and Measures

A hybrid approach was used for capture of all reported AEs following high-dose classic psychedelic exposure and confirmatory capture of AEs of special interest, including suicidality, psychotic disorder, manic symptoms, cardiovascular events, and hallucinogen persisting perception disorder. AEs were stratified by timescale and study population type. Forest plots of common AEs were generated, and the proportions of participants affected by SAEs or NSAEs requiring medical intervention were summarized descriptively.

Results

A total of 214 unique studies were included, of which 114 (53.3%) reported analyzable AE data for 3504 total participants. SAEs were reported for no healthy participants and for approximately 4% of participants with preexisting neuropsychiatric disorders; among these SAEs were worsening depression, suicidal behavior, psychosis, and convulsive episodes. NSAEs requiring medical intervention (eg, paranoia, headache) were similarly rare. In contemporary research settings, there were no reports of deaths by suicide, persistent psychotic disorders, or hallucinogen persisting perception disorders following administration of high-dose classic psychedelics. However, there was significant heterogeneity in the quality of AE monitoring and reporting. Of 68 analyzed studies published since 2005, only 16 (23.5%) described systematic approaches to AE assessment, and 20 studies (29.4%) reported all AEs, as opposed to only adverse drug reactions. Meta-analyses of prevalence for common AEs (eg, headache, anxiety, nausea, fatigue, and dizziness) yielded comparable results for psilocybin and LSD.

Conclusions and Relevance

In this systematic review and meta-analysis, classic psychedelics were generally well tolerated in clinical or research settings according to the existing literature, although SAEs did occur. These results provide estimates of common AE frequencies and indicate that certain catastrophic events reported in recreational or nonclinical contexts have yet to be reported in contemporary trial participants. Careful, ongoing, and improved pharmacovigilance is required to understand the risk and benefit profiles of these substances and to communicate such risks to prospective study participants and the public.

Examining the influence of team-based learning on medical students' comprehension and attitudes regarding psychedelic therapies

INTRODUCTION

This study evaluates the impact of a two-hour team-based learning (TBL) curriculum on medical students' knowledge, comprehension, ethical understanding, and attitudes towards psychedelic therapies.

METHODS

Sixty-three pre-surveys and fifty post-surveys assessed students' perceived knowledge and attitudes using Likert scales. Forty-eight matched pre/post-knowledge tests with multiple-choice questions quantified changes in comprehension. The TBL approach featured independent learning, team readiness assessments, and application exercises.

RESULTS

Post-curriculum, students demonstrated significantly improved test scores (mean 41.4% increase, p < 0.0001) and more positive attitudes across 16 of 18 items (p ≤ 0.0495). Overall attitude scores increased 23% (p < 0.0001). Qualitative feedback reflected enhanced comfort discussing psychedelics clinically. While some students expressed support for psychedelic-assisted therapy, others cited reservations.

DISCUSSION

This innovative curriculum bridged an important education gap given the increasing relevance of psychedelic medicine. Findings suggest TBL enhances medical student preparedness in this emerging field. Continued curricular development is warranted to ensure proper psychedelic education aligns with patient needs and legislative policies. As psychedelic research progresses, maintaining instructional excellence is crucial for future healthcare professionals.

Beyond Psilocybin: Reviewing the Therapeutic Potential of Other Serotonergic Psychedelics in Mental and Substance Use Disorders

There has been a resurgence of interest in the use of psychedelic therapies for several mental and substance use disorders. Psilocybin, a "classic" serotonergic psychedelic, has emerged as one of the primary compounds of interest in clinical research. While research on psilocybin's potential mental health benefits has grown, data on the safety and efficacy of other serotonergic psychedelics remain limited. A comprehensive scoping review on the use of mescaline, ibogaine, ayahuasca, N,N-dimethyltryptamine (DMT), and lysergic acid diethylamide (LSD) in the treatment of mental and substance disorders was conducted. Independent reviewers screened titles, abstracts, and full texts and conducted data extraction. Seventy-seven studies met the inclusion criteria. There were 43 studies of LSD, 24 studies of ayahuasca, 5 studies of DMT, 5 studies of ibogaine, and 5 studies of mescaline. Commonly reported benefits included improved mood and anxiety symptoms, improved insight, reduced substance use, improved relationships, and decreased vegetative symptoms. Commonly reported adverse effects were psychological, neurological, physical, and gastrointestinal in nature. Serious adverse events (homicide and suicide) were reported in published studies of LSD. In conclusion, there is only low-level evidence to support the safety and efficacy of non-psilocybin serotonergic psychedelics in individuals with mental and substance use disorders.

Psychedelic-assisted therapy for palliative care within a home treatment setting: A case report

Key Clinical Message

This case study describes the feasibility and safety of psychedelic-assisted therapy (PAT) as a home-based intervention for a patient with throat cancer experiencing significant existential distress. The patient tolerated the intervention well. This case supports the feasibility and safety of PAT for patients with life-threatening conditions in a home setting.

Abstract

Psychedelic-assisted therapy (PAT), as it is practiced today, merges traditional psychotherapeutic techniques with the use of psychedelics such as LSD, psilocybin, or MDMA with the aim of unlocking deeper insights in patients and treating mental conditions that are resistant to other forms of therapy. The present case study describes the safety of PAT as a home-based intervention for a patient with throat cancer experiencing significant existential distress. The patient tolerated the intervention well and was asked to report on measures of anxiety, depression, and distress related to his somatic condition. The observations provided by this clinical case report align with previous findings, suggesting that PAT can be safely applied to potentially provide relief from existential distress in patients with life-threatening conditions. As this is a single-case study, generalizations should be made cautiously. Moreover, placebo effects, expectancy effects, and the natural course of the disease may influence outcomes. Future research should consider controlled trials to ascertain the efficacy and safety of such interventions in diverse settings.

Therapeutic modulation of the kynurenine pathway in severe mental illness and comorbidities: A potential role for serotonergic psychedelics

Mounting evidence points towards a crucial role of the kynurenine pathway (KP) in the altered gut-brain axis (GBA) balance in severe mental illness (SMI, namely depression, bipolar disorder, and schizophrenia) and cardiometabolic comorbidities. Preliminary evidence shows that serotonergic psychedelics and their analogues may hold therapeutic potential in addressing the altered KP in the dysregulated GBA in SMI and comorbidities. In fact, aside from their effects on mood, psychedelics elicit therapeutic improvement in preclinical models of obesity, metabolic syndrome, and vascular inflammation, which are highly comorbid with SMI. Here, we review the literature on the therapeutic modulation of the KP in the dysregulated GBA in SMI and comorbidities, and the potential application of psychedelics to address the altered KP in the brain and systemic dysfunction underlying SMI and comorbidities. Psychedelics might therapeutically modulate the KP in the altered GBA in SMI and comorbidities either directly, via altering the metabolic pathway by influencing the rate-limiting enzymes of the KP and affecting the levels of available tryptophan, or indirectly, by affecting the gut microbiome, gut metabolome, metabolism, and the immune system. Despite promising preliminary evidence, the mechanisms and outcomes of the KP modulation with psychedelics in SMI and systemic comorbidities remain largely unknown and require further investigation. Several concerns are discussed surrounding the potential side effects of this approach in specific cohorts of individuals with SMI and systemic comorbidities.

Guiding Through Challenging Psychedelic Experiences and "Bad Trips"

Psychedelic substances have gained recognition for their therapeutic potential, but they also present challenges, with individuals occasionally experiencing distressing episodes referred to as challenging experiences or, in the recreational setting, "bad trips". Trial therapists and physicians, but also healthcare professionals in emergency rooms, need a comprehensive strategy to effectively manage these cases. Three case reports are presented to underline the problem and propose strategies for handling these situations. Finally, this article outlines a stepwise approach, encompassing helpful interventions, supportive care, and rescue medication, to ensure the well-being of individuals undergoing challenging psychedelic experiences and prevent further complications and long-term harm.

Comparative oral monotherapy of psilocybin, lysergic acid diethylamide, 3,4-methylenedioxymethamphetamine, ayahuasca, and escitalopram for depressive symptoms: systematic review and Bayesian network meta-analysis

OBJECTIVE

To evaluate the comparative effectiveness and acceptability of oral monotherapy using psychedelics and escitalopram in patients with depressive symptoms, considering the potential for overestimated effectiveness due to unsuccessful blinding.

DESIGN

Systematic review and Bayesian network meta-analysis.

DATA SOURCES

Medline, Cochrane Central Register of Controlled Trials, Embase, PsycINFO, ClinicalTrial.gov, and World Health Organization's International Clinical Trials Registry Platform from database inception to 12 October 2023.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials on psychedelics or escitalopram in adults with depressive symptoms. Eligible randomised controlled trials of psychedelics (3,4-methylenedioxymethamphetamine (known as MDMA), lysergic acid diethylamide (known as LSD), psilocybin, or ayahuasca) required oral monotherapy with no concomitant use of antidepressants.

DATA EXTRACTION AND SYNTHESIS

The primary outcome was change in depression, measured by the 17-item Hamilton depression rating scale. The secondary outcomes were all cause discontinuation and severe adverse events. Severe adverse events were those resulting in any of a list of negative health outcomes including, death, admission to hospital, significant or persistent incapacity, congenital birth defect or abnormality, and suicide attempt. Data were pooled using a random effects model within a Bayesian framework. To avoid estimation bias, placebo responses were distinguished between psychedelic and antidepressant trials.

RESULTS

Placebo response in psychedelic trials was lower than that in antidepression trials of escitalopram (mean difference -3.90 (95% credible interval -7.10 to -0.96)). Although most psychedelics were better than placebo in psychedelic trials, only high dose psilocybin was better than placebo in antidepression trials of escitalopram (mean difference 6.45 (3.19 to 9.41)). However, the effect size (standardised mean difference) of high dose psilocybin decreased from large (0.88) to small (0.31) when the reference arm changed from placebo response in the psychedelic trials to antidepressant trials. The relative effect of high dose psilocybin was larger than escitalopram at 10 mg (4.66 (95% credible interval 1.36 to 7.74)) and 20 mg (4.69 (1.64 to 7.54)). None of the interventions was associated with higher all cause discontinuation or severe adverse events than the placebo.

CONCLUSIONS

Of the available psychedelic treatments for depressive symptoms, patients treated with high dose psilocybin showed better responses than those treated with placebo in the antidepressant trials, but the effect size was small.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42023469014.

Lysergic acid diethylamide induces behavioral changes in Caenorhabditis elegans

Lysergic acid diethylamide (LSD) is a synthetic psychedelic compound with potential therapeutic value for psychiatric disorders. This study aims to establish Caenorhabditis elegans as an in vivo model for examining LSD's effects on locomotor behavior. Our results demonstrate that LSD is absorbed by C. elegans and that the acute treatment reduces animal speed, similar to the role of endogenous serotonin. This response is mediated in part by the serotonergic receptors SER-1 and SER-4. Our findings highlight the potential of this nematode as a new experimental model in psychedelic research.

Ketanserin exhibits dose- and concentration-proportional serotonin 2A receptor occupancy in healthy individuals: Relevance for psychedelic research

The serotonin 2A (5-HT2A) receptor is an important target for drug development and the main receptor through which classical psychedelics elucidate their hallucinogenic effects. The 5-HT2A receptor antagonist ketanserin has frequently been used as a tool to block the receptor. Here, we establish the dose-occupancy relation of ketanserin and the cerebral 5-HT2A receptor in healthy participants by conducting a positron emission tomography (PET) study. 120-min PET scans using the 5-HT2A receptor agonist radiotracer [11C]Cimbi-36 were conducted at baseline and after oral doses of either 10, 20, or 40 mg of ketanserin; each participant underwent one or two scans after ketanserin administration. Occupancy was defined as the percent change in neocortex binding potential (BPND), estimated using the simplified reference tissue model (SRTM) with the cerebellum as reference region. Peroral ketanserin intake resulted in a plasma concentration-related increase in cerebral 5-HT2A receptor occupancy with the highest plasma ketanserin concentrations measured after ∼2 h. The relation between mean plasma ketanserin concentrations and 5-HT2A receptor occupancy conformed to a single-site binding model with an estimated EC50 (95 % CI) of 2.52 (0.75; 8.1) ng/mL, which corresponds to a peroral dose of ketanserin of approximately 10 mg. These data elucidate for the first time in humans the cerebral pharmacodynamics of ketanserin, both benefitting its use as a pharmacological tool for probing brain function and adding to its potential for therapeutic use in rescuing a bad psychedelic experience.

[The nursing role in psychedelic-assisted psychotherapy]

In this article, we aim to highlight the specific role of nurses in the interdisciplinary model of psychedelic-assisted psychotherapy. We argue that the plural competencies of our profession are at the heart of future issues in psychiatry and the use of psychedelics.

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.

LSD-assisted therapy in patients with anxiety: open-label prospective 12-month follow-up

BACKGROUND

Anxiety disorders are a major public health burden with limited treatment options.

AIMS

We investigated the long-term safety and efficacy of lysergic acid diethylamide (LSD)-assisted therapy in patients with anxiety with or without life-threatening illness.

METHOD

This study was an a priori-planned long-term follow-up of an investigator-initiated, two-centre trial that used a double-blind, placebo-controlled, two-period, random-order, crossover design with two sessions with either oral LSD (200 μg) or placebo per period. Participants (n = 39) were followed up 1 year after the end-of-study visit to assess symptoms of anxiety, depression and long-term effects of psychedelics using Spielberger's State-Trait Anxiety Inventory-Global (STAI-G), the Beck Depression Inventory (BDI), the Persisting Effects Questionnaire and measures of personality traits using the NEO-Five-Factor Inventory.

RESULTS

Participants reported a sustained reduction of STAI-G scores compared with baseline (least square means (95% CI) = -21.6 (-32.7, -10.4), d = 1.04, P < 0.001, for those who received LSD in the first period (94 weeks after the last LSD treatment) and -16.5 (-26.2, -6.8), d = 1.02, P < 0.05, for those who received LSD in the second period (68 weeks after the last LSD treatment)). Similar effects were observed for comorbid depression with change from baseline BDI scores of -8.1 (-13.2, -3.1), d = 0.71, P < 0.01, and -8.9 (-12.9, -4.9), d = 1.21, P < 0.01, for the LSD-first and placebo-first groups, respectively. Personality trait neuroticism decreased (P < 0.0001) and trait extraversion increased (P < 0.01) compared with study inclusion. Individuals attributed positive long-term effects to the psychedelic experience.

CONCLUSIONS

Patients reported sustained long-term effects of LSD-assisted therapy for anxiety.

The influence of psilocybin on subconscious and conscious emotional learning

Serotonergic psychedelics hold promise as a treatment modality for various psychiatric disorders and are currently applied in psychedelic-assisted psychotherapy. We investigated the learning effects of the serotonin receptor agonist psilocybin in a probabilistic cue-reward task with emotional cues in the form of neutral or fearful faces, presented either consciously or subconsciously. This study represents the first investigation into reinforcement learning with psilocybin. Across different dosages, psilocybin preserved learning effects and was statistically noninferior compared to placebo, while suggesting a higher exploratory behavior. Notably, the 20 mg group exhibited significantly better learning rates against the placebo group. Psilocybin induced inferior results with subconscious cues compared to placebo, and better results with conscious neutral cues in some conditions. These findings suggest that modulating serotonin signaling in the brain with psilocybin sufficiently preservers reinforcement learning.

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.

In the new era of psychedelic assisted therapy: A systematic review of study methodology in randomized controlled trials

Recent years have seen a resurgence in randomized, placebo controlled trials (RCTs) utilizing non-classical psychedelics (e.g. 3,4-methyl enedioxy methamphetamine [MDMA]), and classical psychedelics (e.g. psilocybin, lysergic acid diethylamide [LSD], and N,N-dimethyltryptamine [DMT/ayahuasca]) in conjunction with assisted therapy (AT) for psychiatric disorders. A notable methodological challenge in psychedelic AT, however, is the complexity of blinding procedures. The lack of efficacious blinding can introduce considerable response bias, reduce internal validity, and compromise participant retention. This systematic review examines design and blinding techniques in RCTs utilizing psychedelics and placebo for the treatment of psychiatric disorders. The aim of this work is to identify factors that may inform future RTC design for conducting psychedelics research. We conducted a systematic review of PubMed, MEDLINE, CINAHL, Cochrane Central Register of Controlled Trials (CENTRAL), Psycinfo, Embase, and Web of Science Core Collection to examine: (1) placebo selection, (2) study design, and (3) integrity of blinding measures. Sixteen publications were identified as meeting the criteria for a systematic review. Our findings suggest that traditional placebo administration is insufficient to control for expectancy confounds. Consequently, experimental methodology that limits personnel unblinding and the use of an active placebo are important considerations when designing prospective clinical studies involving psychedelics.

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.

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.

A Brief Historical Overview of Psychedelic Research

Classical serotonergic psychedelics such as lysergic acid diethylamide or the naturally occurring compounds psilocybin and mescaline produce profound changes in mood, thought, intuition, sensory perception, the experience of time and space, and even the experience of self. Research examining psychedelic compounds has had a complex and turbulent evolution. Many cultures throughout the world have used psychedelic plants not only for mystical, ritualistic, or divinatory purposes but also for curing illnesses. Much of the genesis and progress of modern investigations into the effects and underlying mechanisms of action of psychedelics have been intertwined with studies of the neurotransmitter serotonin. Early hypotheses that serotonergic systems mediate psychedelic effects were supported initially by preclinical animal studies and subsequently confirmed by pharmacological studies in healthy humans. The use of psychedelic compounds as putative psychotomimetics that reproduce some features of naturally occurring psychotic disorders met with some limited success. More recent studies are exploring psychedelics as potential psychotherapeutic agents. Recent indications that even 1 or 2 psychedelic treatments produce robust and sustained reductions in clinical symptoms in a variety of psychiatric disorders have prompted an enormous resurgence of interest in the nature and mechanisms contributing to their effects.

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.

Effective Connectivity of Thalamocortical Interactions Following d-Amphetamine, LSD, and MDMA Administration

BACKGROUND

While the exploration of serotonergic psychedelics as psychiatric medicines deepens, so does the pressure to better understand how these compounds act on the brain.

METHODS

We used a double-blind, placebo-controlled, crossover design and administered lysergic acid diethylamide (LSD), 3,4-methylenedioxymethamphetamine (MDMA), and d-amphetamine in 25 healthy participants. By using spectral dynamic causal modeling, we mapped substance-induced changes in effective connectivity between the thalamus and different cortex types (unimodal vs. transmodal) derived from a previous study with resting-state functional magnetic resonance imaging data. Due to the distinct pharmacological modes of action of the 3 substances, we were able to investigate specific effects mainly driven by different neurotransmitter systems on thalamocortical and corticothalamic interactions.

RESULTS

Compared with placebo, all 3 substances increased the effective connectivity from the thalamus to specific unimodal cortices, whereas the influence of these cortices on the thalamus was reduced. These results indicate increased bottom-up and decreased top-down information flow between the thalamus and some unimodal cortices. However, for the amphetamines, we found the opposite effects when examining the effective connectivity with transmodal cortices, including parts of the salience network. Intriguingly, LSD increased the effective connectivity from the thalamus to both unimodal and transmodal cortices, indicating a breach in the hierarchical organization of ongoing brain activity.

CONCLUSIONS

The results advance our knowledge about the action of psychedelics on the brain and refine current models aiming to explain the underlying neurobiological processes.

Neurochemical and Neurophysiological Effects of Intravenous Administration of N,N-dimethyltryptamine in Rats

N,N-dimethyltryptamine (DMT) is a serotonergic psychedelic that is being investigated clinically for the treatment of psychiatric disorders. Although the neurophysiological effects of DMT in humans are well-characterized, similar studies in animal models as well as data on the neurochemical effects of DMT are generally lacking, which are critical for mechanistic understanding. In the current study, we combined behavioral analysis, high-density (32-channel) electroencephalography, and ultra-high-performance liquid chromatography-tandem mass spectrometry to simultaneously quantify changes in behavior, cortical neural dynamics, and levels of 17 neurochemicals in medial prefrontal and somatosensory cortices before, during, and after intravenous administration of three different doses of DMT (0.75 mg/kg, 3.75 mg/kg, 7.5 mg/kg) in male and female adult rats. All three doses of DMT produced head twitch response with most twitches observed after the low dose. DMT caused dose-dependent increases in serotonin and dopamine levels in both cortical sites along with a reduction in EEG spectral power in theta (4-10 Hz) and low gamma (25-55 Hz), and increase in power in delta (1-4 Hz), medium gamma (65-115), and high gamma (125-155 Hz) bands. Functional connectivity decreased in the delta band and increased across the gamma bands. In addition, we provide the first measurements of endogenous DMT in these cortical sites at levels comparable to serotonin and dopamine, which together with a previous study in occipital cortex, suggests a physiological role for endogenous DMT. This study represents one of the most comprehensive characterizations of psychedelic drug action in rats and the first to be conducted with DMT.

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.

[Towards a Better understanding of Persisting Perceptual Disturbances following the use of Classic Psychedelics.]

Klassische Psychedelika wie Psilocybin, Lysergsäurediethylamid (LSD), Ayahuasca oder 5-Methoxy-Dimethyltryptamin (5-MeO-DMT) stehen wieder vermehrt im Fokus des psychiatrisch-psychotherapeutischen und neurowissenschaftlichen Interesses. Dies ist vor allem auf aktuelle klinische Studien zurückzuführen, die einen möglichen therapeutischen Nutzen von Psychedelika in der Behandlung verschiedener psychischer Störungen nahelegen, wie bei therapieresistenten Depressionen, Abhängigkeitserkrankungen, Angststörungen und existentiellen Ängsten bei lebensbedrohlichen körperlichen Erkrankungen 1 2 3 4. Trotz der beobachteten vielversprechenden Effekte ist es wichtig zu betonen, dass Psychedelika auch potenzielle Risiken bergen, die sie von vielen anderen psychoaktiven Substanzen unterscheiden. Diese liegen in der besonderen Phänomenologie der Wirkungen dieser Substanzen auf das zentrale Nervensystem und die menschliche Psyche begründet, in der zeitlichen Dynamik ihrer psychologischen Effekte, und in ihrem biologischen Wirkprofil.

Greater subjective effects of a low dose of LSD in participants with depressed mood

Recent studies and anecdotal reports suggest that psychedelics can improve mood states, even at low doses. However, few placebo-controlled studies have examined the acute effects of low doses of LSD in individuals with psychiatric symptoms. In the current study, we examined the acute and sub-acute effect of a low dose of LSD (26 µg) on subjective effects and mood in volunteers with mild depressed mood. The study used a randomized, double-blind, crossover design to compare the effects of LSD in two groups of adults: participants who scored high (≥17; n = 20) or low (<17; n = 19) on the Beck Depression-II inventory (BDI) at screening. Participants received a single low dose of LSD (26 µg) and placebo during two 5-h laboratory sessions, separated by at least one week. Subjective, physiological, and mood measures were assessed at regular intervals throughout the sessions, and behavioral measures of creativity and emotion recognition were obtained at expected peak effect. BDI depression scores and mood ratings were assessed 48-h after each session. Relative to placebo, LSD (26 µg) produced expected, mild physiological and subjective effects on several measures in both groups. However, the high BDI group reported significantly greater drug effects on several indices of acute effects, including ratings of vigor, elation, and affectively positive scales of a measure of psychedelic effects (5D-ASC). The high BDI group also reported a greater decline in BDI depression scores 48-h after LSD, compared to placebo. These findings suggest that an acute low dose of LSD (26 µg) elicits more pronounced positive mood and stimulant-like effects, as well as stronger altered states of consciousness in individuals with depressive symptoms, compared to non-depressed individuals.

The novel non-hallucinogenic compound DM506 (3-methyl-1,2,3,4,5,6-hexahydroazepino[4,5-b]indole) induces sedative- and anxiolytic-like activity in mice by a mechanism involving 5-HT2A receptor activation

The anxiolytic and sedative-like effects of 3-methyl-1,2,3,4,5,6-hexahydroazepino[4,5-b]indole (DM506), a non-hallucinogenic compound derived from ibogamine, were studied in mice. The behavioral effects were examined using Elevated O-maze and novelty suppressed feeding (NSFT) tests, open field test, and loss of righting reflex (LORR) test. The results showed that 15 mg/kg DM506 induced acute and long-lasting anxiolytic-like activity in naive and stressed/anxious mice, respectively. Repeated administration of 5 mg/kg DM506 did not cause cumulative anxiolytic activity or any side effects. Higher doses of DM506 (40 mg/kg) induced sedative-like activity, which was inhibited by a selective 5-HT2A receptor antagonist, volinanserin. Electroencephalography results showed that 15 mg/kg DM506 fumarate increased the transition from a highly alert state (fast γ wavelength) to a more synchronized deep-sleeping activity (δ wavelength), which is reflected in the sedative/anxiolytic activity in mice but without the head-twitch response observed in hallucinogens. The functional, radioligand binding, and molecular docking results showed that DM506 binds to the agonist sites of human 5-HT2A (Ki = 24 nM) and 5-HT2B (Ki = 16 nM) receptors and activates them with a potency (EC50) of 9 nM and 3 nM, respectively. DM506 was relatively less potent and behaved as a partial agonist (efficacy <80%) for both receptor subtypes compared to the full agonist DOI (2,5-dimethoxy-4-iodoamphetamine). Our study showed for the first time that the non-hallucinogenic compound DM506 induces anxiolytic- and sedative-like activities in naïve and stressed/anxious mice in a dose-, time-, and volinanserin-sensitive manner, likely through mechanisms involving 5-HT2A receptor activation.

Development of the Japanese version of the 30-item Mystical Experience Questionnaire

INTRODUCTION

Psychedelics have garnered increased attention as potential therapeutic options for various mental illnesses. Previous studies reported that psychedelics cause psychoactive effects through mystical experiences induced by these substances, including an altered state of consciousness. While this phenomenon is commonly assessed by the Mystical Experiences Questionnaire (MEQ30), a Japanese version of the MEQ30 has not been available. The aim of this study was to develop the Japanese version of the MEQ30.

METHODS

We adhered to 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" in our translation process. Two Japanese psychiatrists independently performed forward translations, from which a unified version was derived through reconciliation. This version was subsequently back-translated into English and reviewed by the original authors for equivalency. The iterative revision process was carried out through ongoing discussions with the original authors until they approved the final back-translated version.

RESULTS

The final, approved back-translated version of the MEQ30 is presented in the accompanying figure. Additionally, the authorized Japanese version of the MEQ30 is included in the Appendix A.

CONCLUSIONS

In this study, we successfully developed a Japanese version of the MEQ30. This scale will facilitate the assessment of mystical experiences associated with psychedelic-assisted therapy among Japanese speakers. Further research is warranted to evaluate the reliability and validity of this newly translated scale.

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.

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.

Are "mystical experiences" essential for antidepressant actions of ketamine and the classic psychedelics?

The growing interest in the rapid and sustained antidepressant effects of the dissociative anesthetic ketamine and classic psychedelics, such as psilocybin, is remarkable. However, both ketamine and psychedelics are known to induce acute mystical experiences; ketamine can cause dissociative symptoms such as out-of-body experience, while psychedelics typically bring about hallucinogenic experiences, like a profound sense of unity with the universe or nature. The role of these mystical experiences in enhancing the antidepressant outcomes for patients with depression is currently an area of ongoing investigation and debate. Clinical studies have shown that the dissociative symptoms following the administration of ketamine or (S)-ketamine (esketamine) are not directly linked to their antidepressant properties. In contrast, the antidepressant potential of (R)-ketamine (arketamine), thought to lack dissociative side effects, has yet to be conclusively proven in large-scale clinical trials. Moreover, although the activation of the serotonin 5-HT2A receptor is crucial for the hallucinogenic effects of psychedelics in humans, its precise role in their antidepressant action is still under discussion. This article explores the importance of mystical experiences in enhancing the antidepressant efficacy of both ketamine and classic psychedelics.

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.

Exploring Novel Antidepressants Targeting G Protein-Coupled Receptors and Key Membrane Receptors Based on Molecular Structures

Major Depressive Disorder (MDD) is a complex mental disorder that involves alterations in signal transmission across multiple scales and structural abnormalities. The development of effective antidepressants (ADs) has been hindered by the dominance of monoamine hypothesis, resulting in slow progress. Traditional ADs have undesirable traits like delayed onset of action, limited efficacy, and severe side effects. Recently, two categories of fast-acting antidepressant compounds have surfaced, dissociative anesthetics S-ketamine and its metabolites, as well as psychedelics such as lysergic acid diethylamide (LSD). This has led to structural research and drug development of the receptors that they target. This review provides breakthroughs and achievements in the structure of depression-related receptors and novel ADs based on these. Cryo-electron microscopy (cryo-EM) has enabled researchers to identify the structures of membrane receptors, including the N-methyl-D-aspartate receptor (NMDAR) and the 5-hydroxytryptamine 2A (5-HT2A) receptor. These high-resolution structures can be used for the development of novel ADs using virtual drug screening (VDS). Moreover, the unique antidepressant effects of 5-HT1A receptors in various brain regions, and the pivotal roles of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) and tyrosine kinase receptor 2 (TrkB) in regulating synaptic plasticity, emphasize their potential as therapeutic targets. Using structural information, a series of highly selective ADs were designed based on the different role of receptors in MDD. These molecules have the favorable characteristics of rapid onset and low adverse drug reactions. This review offers researchers guidance and a methodological framework for the structure-based design of ADs.

Effects of DMT on mental health outcomes in healthy volunteers

Psilocybin, a serotonergic psychedelic, is being increasingly researched in clinical studies for the treatment of psychiatric disorders. The relatively lengthy duration of oral psilocybin's acute effects (4-6 h) may have pragmatic and cost-effectiveness limitations. Here, we explored the effects of intravenous (IV) N,N-Dimethyltryptamine (DMT), a closely related, but faster-acting psychedelic intervention, on mental health outcomes in healthy volunteers. Data is reported from two separate analyses: (1) A comparison of mental health-related variables 1 week after 7, 14, 18, and 20 mg of IV DMT versus IV saline placebo (n = 13) and, (2) A prospective dataset assessing effects before versus 2 weeks after 20 mg of IV DMT (n = 17). Mental health outcomes included measures of depression severity (QIDS-SR16), trait anxiety (STAI-T), Neuroticism (NEO-FFI), wellbeing (WHO-5), meaning in life (MLQ), optimism (LOT-R), and gratitude (GQ-6). In both the prospective and placebo-controlled datasets, significant improvements in scores of depression were found 1-2 weeks after DMT administration. Significant reductions in trait Neuroticism were only found for the placebo-controlled sample. Finally, changes in depression and trait anxiety correlated with acute peak experiences (assessed via 'Oceanic Boundlessness'). While the use of two separate cohorts in pooled analysis limits the generalizability of these correlational findings, these results suggest that DMT may reduce depressive symptomatology by inducing peak experiences. The short half-life of IV DMT and its potential for flexible dosing via controlled infusions makes it an appealing candidate for psychedelic medicine. Further research in clinical samples is needed to corroborate the therapeutic potential of DMT.

Synthetic surprise as the foundation of the psychedelic experience

Psychedelic agents, such as LSD and psilocybin, induce marked alterations in consciousness via activation of the 5-HT2A receptor (5-HT2ARs). We hypothesize that psychedelics enforce a state of synthetic surprise through the biased activation of the 5-HTRs system. This idea is informed by recent insights into the role of 5-HT in signaling surprise. The effects on consciousness, explained by the cognitive penetrability of perception, can be described within the predictive coding framework where surprise corresponds to prediction error, the mismatch between predictions and actual sensory input. Crucially, the precision afforded to the prediction error determines its effect on priors, enabling a dynamic interaction between top-down expectations and incoming sensory data. By integrating recent findings on predictive coding circuitry and 5-HT2ARs transcriptomic data, we propose a biological implementation with emphasis on the role of inhibitory interneurons. Implications arise for the clinical use of psychedelics, which may rely primarily on their inherent capacity to induce surprise in order to disrupt maladaptive patterns.

Magnesium-ibogaine therapy in veterans with traumatic brain injuries

Traumatic brain injury (TBI) is a leading cause of disability. Sequelae can include functional impairments and psychiatric syndromes such as post-traumatic stress disorder (PTSD), depression and anxiety. Special Operations Forces (SOF) veterans (SOVs) may be at an elevated risk for these complications, leading some to seek underexplored treatment alternatives such as the oneirogen ibogaine, a plant-derived compound known to interact with multiple neurotransmitter systems that has been studied primarily as a treatment for substance use disorders. Ibogaine has been associated with instances of fatal cardiac arrhythmia, but coadministration of magnesium may mitigate this concern. In the present study, we report a prospective observational study of the Magnesium-Ibogaine: the Stanford Traumatic Injury to the CNS protocol (MISTIC), provided together with complementary treatment modalities, in 30 male SOVs with predominantly mild TBI. We assessed changes in the World Health Organization Disability Assessment Schedule from baseline to immediately (primary outcome) and 1 month (secondary outcome) after treatment. Additional secondary outcomes included changes in PTSD (Clinician-Administered PTSD Scale for DSM-5), depression (Montgomery-Åsberg Depression Rating Scale) and anxiety (Hamilton Anxiety Rating Scale). MISTIC resulted in significant improvements in functioning both immediately (Pcorrected < 0.001, Cohen's d = 0.74) and 1 month (Pcorrected < 0.001, d = 2.20) after treatment and in PTSD (Pcorrected < 0.001, d = 2.54), depression (Pcorrected < 0.001, d = 2.80) and anxiety (Pcorrected < 0.001, d = 2.13) at 1 month after treatment. There were no unexpected or serious adverse events. Controlled clinical trials to assess safety and efficacy are needed to validate these initial open-label findings. ClinicalTrials.gov registration: NCT04313712 .

Interactions between classic psychedelics and serotonergic antidepressants: Effects on the acute psychedelic subjective experience, well-being and depressive symptoms from a prospective survey study

BACKGROUND

There is growing evidence for the therapeutic effects of psychedelics. However, it is still uncertain how these drugs interact with serotonergic antidepressants (serotonin reuptake inhibitors (SRIs)).

OBJECTIVE

This study explores the interaction between psychedelics and SRIs in terms of therapeutic effects. The objective is to compare acute psychedelic effects and subsequent changes in well-being and depressive symptoms among 'SRI -' individuals (not on psychiatric medication) and 'SRI +' individuals (undergoing SRI treatment).

METHODS

Using prospective survey data, the study employs multivariate analysis of covariance (MANCOVA) and linear mixed effect models to analyse subjective differences and changes in well-being and depressive symptoms pre- and post-psychedelic experiences.

RESULTS

Results indicate that 'SRI -' participants experience significantly more intense subjective effects compared to 'SRI +' participants (F = 3.200, p = 0.016) in MANCOVA analysis. Further analysis reveals 'SRI -' individuals report stronger mystical (18.2% higher, p = 0.048), challenging (50.9% higher, p = 0.001) and emotional breakthrough experiences (31.9% higher, p = 0.02) than 'SRI +' individuals. No differences are observed in drug-induced visual effects (p = 0.19). Both groups exhibited similar improvements in well-being and depressive symptoms after the psychedelic experience.

CONCLUSION

Individuals presumed to be on serotonergic antidepressants during psychedelic use display reduced subjective effects but similar antidepressant effects compared to those not undergoing SRI treatment. Further controlled research is needed to comprehend the interplay between serotonergic antidepressants and psychedelics, illuminating potential therapeutic benefits and limitations in clinical contexts.

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.