Assessing the risk-benefit profile of classical psychedelics: a clinical review of second-wave psychedelic research

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.

Comparison between Single-Dose and Two-Dose Psilocybin Administration in the Treatment of Major Depression: A Systematic Review and Meta-Analysis of Current Clinical Trials

Current pharmacological treatments for major depressive disorder (MDD) are often only partially effective, with many patients experiencing no significant benefit, leading to treatment-resistant depression (TRD). Psilocybin, a classical serotonergic psychedelic, has emerged as a notable emerging treatment for such disorders. The aim of this systematic review and meta-analysis is to summarize and discuss the most recent evidence about the therapeutic effects of single-dose and two-dose psilocybin administration on the severity of depressive symptoms, as well as compare the efficacy of these interventions among patients with a primary diagnosis of MDD or TRD. Articles were collected from EBSCOhost and PubMed following the PRISMA guidelines, yielding 425 articles with 138 duplicates. After screening 287 records, 12 studies met the eligibility criteria and were included in the review. A quantitative analysis of the studies indicates that psilocybin is highly effective in reducing depressive symptoms severity among patients with primary MDD or TRD. Both single-dose and two-dose psilocybin treatments significantly reduced depressive symptoms severity, with two-dose administration sometimes yielding more pronounced and lasting effects. However, it is unclear if this was solely due to dosage or other factors. Future research should include standardized trials comparing these dosing strategies to better inform clinical practice.

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

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

Attitudes on Psychedelics in a Sample of Croatian Mental Health Professionals: A Cross-Sectional National Survey Study

For some time now, there has been an increased interest in psychedelics among scientists and mental health experts. Given that experts introduce therapy and advise patients, it is important to know their views. Therefore, the aim of our research was to examine and compare the attitudes of psychiatrists and psychologists toward psychedelics. We were interested in how they are formed and what is the role of personality in that process. We included 218 respondents, of which 92 were psychiatrists and 126 were psychologists. Attitudes toward psychedelics were examined using the Attitudes on Psychedelics Questionnaire. We used the Big Five Inventory to examine personality traits. On the Legal Use of Psychedelics subscale, it was shown that psychiatrists have more negative attitudes toward psychedelics (p = .033). Higher Openness (β = 0.184, p < .001) and lower Conscientiousness (β = -0.144, p = .009) contribute to positive attitudes toward psychedelics, as well as previous lifetime experience with psychedelics (β = 0.411, p < .001) and younger age (β = -0.278, p < .001). In conclusion, we can say that mental health professionals are open but also wary of psychedelics. Openness motivates them to learn. For this reason, additional education could have an impact on the attitudes of psychiatrists and psychologists and prepare them for the practical use of psychedelics.

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

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

Commentary: Evidence-Informed Recommendation to Achieve Approximate Parity in the Allowed Number of Doses for Common Psychedelics

In recent years, policymakers have proposed and implemented regulatory changes promoting the deprioritization, decriminalization, or state-level legalization of one or more psychedelic substances, usually referencing data from clinical trials as reasons to support liberalizing drug control policies. As psychedelic policies continue to be drafted, personal possession limits may be considered for inclusion in those regulations. If "allowable amount" limits are to be written into law to set personal possession limits, then such amounts should be more consistently related to psychedelic doses found to be safe and efficacious in clinical trials, existing data on moderate-high doses commonly used in various naturalistic settings, and the few studies that estimate psychedelic dose equivalence based on the intensity of subjective effects. In this commentary, we provide an evidence-informed table of typical moderate-high doses for seven commonly used psychedelic substances. These estimates of comparable moderate-high doses can be used to inform "allowable amount" values for psychedelic substances. When such limits are written into legislation, the adoption of evidence-informed comparable limits akin to those presented here would be an important first step toward ensuring greater parity and consistency in drug policy, relative to limits that have little or no scientific basis.

Giving Consent to the Ineffable

A psychedelic renaissance is currently taking place in mental healthcare. The number of psychedelic-assisted therapy trials is growing steadily, and some countries already grant psychiatrists special permission to use psychedelics in non-research contexts under certain conditions. These clinical advances must be accompanied by ethical inquiry. One pressing ethical question involves whether patients can even give informed consent to psychedelic-assisted therapy: the treatment's transformative nature seems to block its assessment, suggesting that patients are unable to understand what undergoing psychedelic-assisted therapy actually means for them and whether it aligns with their values. The present paper argues that patients often have sufficient knowledge to give informed consent because they know that they want to change their negative status quo and that psychedelic-assisted therapy offers an effective way to do so. Accordingly, patients can understand what the transformative nature of psychedelic-assisted therapy means for them and a make a value-aligned choice even if they are unable to anticipate the manifestation of a psychedelic experience.

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.

Trauma-Informed Care in Psychedelic Therapy Research: A Qualitative Literature Review of Evidence-Based Psychotherapy Interventions in PTSD and Psychedelic Therapy Across Conditions

Introduction

Post-traumatic stress disorder (PTSD) is associated with significant patient burden. While pharmacotherapies and evidence-based psychotherapy interventions (EBPI) are effective, studies consistently highlight inadequate outcomes and high treatment dropout. Psychedelic therapy (PT) has shown preliminary promise across difficult-to-treat conditions, including MDMA-assisted therapy for PTSD, however trials of classical psychedelics in PTSD are lacking. Understanding patients' experiences of EBPI could help promote safety in PT.

Aim

To systematically review qualitative research on patients' subjective experience of EBPI for PTSD, and of PT, and examine areas of overlap and divergence between them.

Methods

Systematic literature searches for studies published between 2010 and 2023 were conducted on OVID, PubMed, Web of Science, and PsycInfo. Included were original studies in English that presented qualitative data of patient experiences of EBPI in PTSD, or PT for any indication. Extracted data from included studies were analysed using thematic synthesis. Syntheses were completed separately for EBPI and PT, before similarities and differences between the therapies were identified.

Results

40 research articles were included for review: 26 studies on EBPI for PTSD, and 14 studies on PT. EBPI studied were CBT, EMDR, CPT and PE. Psychedelic compounds studied were psilocybin, ibogaine, LSD, MDMA and ketamine, for treatment of substance use disorders, anxiety relating to physical illness, depression, and PTSD. Core themes from patient experiences of EBPI: 1) patient burden in PTSD treatment; 2) readiness; 3) key mechanisms of change; 4) psychological safety and trust. Themes identified in the review of PT: 1) indirect trauma processing; 2) reorganisation of self-narratives via processes of relatedness and identification; 3) key treatment characteristics.

Conclusion

This study suggests overlap between patients' experience of EBPI and PT in terms of key mechanisms of change, the importance of psychological safety and readiness to engage in treatment. Trauma-informed care paradigms and practices may improve safety and acceptability of PT research.

Serotonin 2A Receptor (5-HT2AR) Agonists: Psychedelics and Non-Hallucinogenic Analogues as Emerging Antidepressants

Psychedelics make up a group of psychoactive compounds that induce hallucinogenic effects by activating the serotonin 2A receptor (5-HT2AR). Clinical trials have demonstrated the traditional psychedelic substances like psilocybin as a class of rapid-acting and long-lasting antidepressants. However, there is a pressing need for rationally designed 5-HT2AR agonists that possess optimal pharmacological profiles in order to fully reveal the therapeutic potential of these agonists and identify safer drug candidates devoid of hallucinogenic effects. This Perspective provides an overview of the structure-activity relationships of existing 5-HT2AR agonists based on their chemical classifications and discusses recent advancements in understanding their molecular pharmacology at a structural level. The encouraging clinical outcomes of psychedelics in depression treatment have sparked drug discovery endeavors aimed at developing novel 5-HT2AR agonists with improved subtype selectivity and signaling bias properties, which could serve as safer and potentially nonhallucinogenic antidepressants. These efforts can be significantly expedited through the utilization of structure-based methods and functional selectivity-directed screening.

Psychedelic therapies reconsidered: compounds, clinical indications, and cautious optimism

The clinical investigation of psychedelic medicines has blossomed over the last 5 years. Data from a Phase 3 industry trial and a multicenter Phase 2 industry trial, in addition to multiple early phase investigator-initiated and industry trials, have now been published in peer-reviewed journals. This narrative review summarizes both the recent data and the current clinical trials that are being conducted with various classes of "psyche-manifesting" substances, which may prove beneficial in the treatment of a broad range of conditions. Methodological considerations, unique challenges, and next steps for research are discussed in keeping with the uniquely "experiential" nature of these therapies.

The Relationship Between Naturalistic Psychedelic Use and Clinical Care in Canada

Naturalistic psychedelic use among Canadians is common. However, interactions about psychedelic use between patients and clinicians in Canada remain unclear. Via an anonymous survey, we assessed health outcomes and integration of psychedelic use with health care providers (HCP) among Canadian adults reporting past use of a psychedelic. The survey included 2,384 participants, and most (81.2%) never discussed psychedelic use with their HCP. While 33.7% used psychedelics to self-treat a health condition, only 4.4% used psychedelics with a therapist and 3.6% in a clinical setting. Overall, 44.8% (n = 806) of participants were aware of substance testing services, but only 42.4% ever used them. Multivariate regressions revealed that therapeutic motivation, higher likelihood of seeking therapist guidance, and non-binary gender identification were significantly associated with higher odds of discussing psychedelics with one's primary HCP. Having used a greater number of psychedelics, lower age, non-female gender, higher education, and a therapeutic motivation were significantly associated with higher odds of awareness of substance testing. We conclude that naturalistic psychedelic use in Canada often includes therapeutic goals but is poorly connected to conventional healthcare, and substance testing is uncommon. Relevant training and education for HCPs is needed, along with more visible options for substance testing.

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

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

Chasing the Numinous: Hungry Ghosts in the Shadow of the Psychedelic Renaissance

In recent years a renewed scientific, public and commercial interest in psychedelic medicines can be observed across the globe. As research findings have been generally promising, there is hope for new treatment possibilities for a number of difficult-to-treat mental health concerns. While honouring positive developments and therapeutic promise in relation to the medical use of psychedelics, this paper aims to shine a light on some underlying psycho-cultural shadow dynamics in the unfolding psychedelic renaissance. This paper explores whether and how the multi-layered collective fascination with psychedelics may yet be another symptom pointing towards a deeper psychological and spiritual malaise in the modern Western psyche as diagnosed by C. G. Jung. The question is posed whether the West's feverish pursuit of psychedelic medicines-from individual consumption to entheogenic tourism, from capitalist commodification of medicines and treatments to the increasing number of ethical scandals and abuse through clinicians and self-proclaimed shamans-is related to a Western cultural complex. As part of the discussion, the archetypal image of the Hungry Ghost, known across Asian cultural and religious traditions, is explored to better understand the aforementioned shadow phenomena and point towards mitigating possibilities.

Psychedelics for treatment resistant depression: are they game changers?

INTRODUCTION

A new era of treatment for adults with treatment-resistant depression (TRD), which involves psychedelic substances, is dawning. Emerging evidence indicates that psychedelics can exert antidepressant effects through multiple neurobiological and psychological mechanisms. However, it remains to be seen if these new treatments will revolutionize the treatment of TRD.

AREAS COVERED

The present review focuses on the efficacy of serotoninergic psychedelics psilocybin, lysergic acid diethylamide (LSD), N,N-dimethyltryptamine (DMT), ayahuasca, 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and mescaline (3,4,5-trimethoxyphenethylamine), as well as 3,4-methylenedioxymethamphetamine (MDMA), for TRD. A systematic search was conducted for psilocybin in TRD as emerging trials had not yet been subject to review. A narrative review summarized findings on other psychedelics.

EXPERT OPINION

Psychedelic therapy has created a paradigm shift in the treatment of TRD, as it can maximize therapeutic benefits and minimize potential risks. Psilocybin holds promise as a potential game-changer in the treatment of TRD, with initial evidence suggesting a rapid antidepressant effect sustained for some responders for at least 3 months. Nevertheless, further adequately powered, double-blind, comparator-controlled trials are required to explore and clarify the mechanisms of action and long-term effects of psychedelics in TRD. Psychedelics also hold promise for other psychiatric conditions, such as bipolar depression and post-traumatic stress disorder.

Effects of serotonergic psychedelics on mitochondria: Transdiagnostic implications for mitochondria-related pathologies

The use of serotonergic psychedelics has gained increasing attention in research, clinical practice and society. Growing evidence suggests fast-acting, transdiagnostic health benefits of these 5-hydroxytryptamine 2A receptor agonists. Here, we provide a brief overview of their benefits for psychological, cardiovascular, metabolic, neurodegenerative, and immunological pathologies. We then review their effect on mitochondria including mitochondrial biogenesis, functioning and transport. Mitochondrial dysregulation is a transdiagnostic mechanism that contributes to the aforementioned pathologies. Hence, we postulate that psychedelic-induced effects on mitochondria partially underlie their transdiagnostic benefits. Based on this assumption, we propose new treatment indications for psychedelics and that the health benefits induced by psychedelics depend on patient-specific mitochondrial dysregulation.

The Missing Piece? A Case for Microglia's Prominent Role in the Therapeutic Action of Anesthetics, Ketamine, and Psychedelics

There is much excitement surrounding recent research of promising, mechanistically novel psychotherapeutics - psychedelic, anesthetic, and dissociative agents - as they have demonstrated surprising efficacy in treating central nervous system (CNS) disorders, such as mood disorders and addiction. However, the mechanisms by which these drugs provide such profound psychological benefits are still to be fully elucidated. Microglia, the CNS's resident innate immune cells, are emerging as a cellular target for psychiatric disorders because of their critical role in regulating neuroplasticity and the inflammatory environment of the brain. The following paper is a review of recent literature surrounding these neuropharmacological therapies and their demonstrated or hypothesized interactions with microglia. Through investigating the mechanism of action of psychedelics, such as psilocybin and lysergic acid diethylamide, ketamine, and propofol, we demonstrate a largely under-investigated role for microglia in much of the emerging research surrounding these pharmacological agents. Among others, we detail sigma-1 receptors, serotonergic and γ-aminobutyric acid signalling, and tryptophan metabolism as pathways through which these agents modulate microglial phagocytic activity and inflammatory mediator release, inducing their therapeutic effects. The current review includes a discussion on future directions in the field of microglial pharmacology and covers bidirectional implications of microglia and these novel pharmacological agents in aging and age-related disease, glial cell heterogeneity, and state-of-the-art methodologies in microglial research.

Investigation of self-treatment with lysergic acid diethylamide and psilocybin mushrooms: Findings from the Global Drug Survey 2020

BACKGROUND

Growing numbers of people are using psychedelics for personal psychotherapy outside clinical settings, but research on such use is scarce.

AIMS

This study investigated the patterns of use, self-reported outcomes and outcome predictors of psychedelic 'self-treatment' of mental health conditions or specific worries/concerns in life.

METHODS

We use data from the Global Drug Survey 2020, a large online survey on drug use collected between November 2019 and February 2020. In all, 3364 respondents reported their self-treatment experiences with lysergic acid diethylamide (N = 1996) or psilocybin mushrooms (N = 1368). The primary outcome of interest was the 17-item self-treatment outcome scale, items reflecting aspects of well-being, psychiatric symptoms, social-emotional skills, and health behaviours.

RESULTS

Positive changes were observed across all 17 outcome items, with the strongest benefits on items related to insight and mood. Negative effects were reported by 22.5% of respondents. High intensity of psychedelic experience, seeking advice before treatment, treating with psilocybin mushrooms and treating post-traumatic stress disorder were associated with higher scores on the self-treatment outcome scale after averaging values across all 17 items. Younger age, high intensity of experience and treating with LSD were associated with increased number of negative outcomes.

CONCLUSIONS

This study brings important insights into self-treatment practices with psychedelics in a large international sample. Outcomes were generally favourable, but negative effects appeared more frequent than in clinical settings. Our findings can help inform safe practices of psychedelic use in the community, and inspire clinical research. Future research can be improved with utilisation of prospective designs and additional predictive variables.

The Canadian Network for Mood and Anxiety Treatments (CANMAT) Task Force Report: Serotonergic Psychedelic Treatments for Major Depressive Disorder

OBJECTIVE

Serotonergic psychedelics are re-emerging as potential novel treatments for several psychiatric disorders including major depressive disorder. The Canadian Network for Mood and Anxiety Treatments (CANMAT) convened a task force to review the evidence and provide a consensus recommendation for the clinical use of psychedelic treatments for major depressive disorder.

METHODS

A systematic review was conducted to identify contemporary clinical trials of serotonergic psychedelics for the treatment of major depressive disorder and cancer-related depression. Studies published between January 1990 and July 2021 were identified using combinations of search terms, inspection of bibliographies and review of other psychedelic reviews and consensus statements. The levels of evidence for efficacy were graded according to the Canadian Network for Mood and Anxiety Treatments criteria.

RESULTS

Only psilocybin and ayahuasca have contemporary clinical trials evaluating antidepressant effects. Two pilot studies showed preliminary positive effects of single-dose ayahuasca for treatment-resistant depression (Level 3 evidence). Small randomized controlled trials of psilocybin combined with psychotherapy showed superiority to waitlist controls and comparable efficacy and safety to an active comparator (escitalopram with supportive psychotherapy) in major depressive disorder, with additional randomized controlled trials showing efficacy specifically in cancer-related depression (Level 3 evidence). There was only one open-label trial of psilocybin in treatment-resistant unipolar depression (Level 4 evidence). Small sample sizes and functional unblinding were major limitations in all studies. Adverse events associated with psychedelics, including psychological (e.g., psychotomimetic effects) and physical (e.g., nausea, emesis and headaches) effects, were generally transient.

CONCLUSIONS

There is currently only low-level evidence to support the efficacy and safety of psychedelics for major depressive disorder. In Canada, as of 2022, psilocybin remains an experimental option that is only available through clinical trials or the special access program. As such, Canadian Network for Mood and Anxiety Treatments considers psilocybin an experimental treatment and recommends its use primarily within clinical trials, or, less commonly, through the special access program in rare, special circumstances.

Ibogaine/Noribogaine in the Treatment of Substance Use Disorders: A Systematic Review of the Current Literature

BACKGROUND

Ibogaine and noribogaine are psychedelic substances with dissociative properties naturally occurring in plants of the Apocynaceae family. Research has shown their efficacy in treating substance use disorders (SUD), particularly in opiate detoxification, but their efficacy and toxicity are still unclear.

OBJECTIVE

This review aims to assess the anti-addictive role of ibogaine and evaluate its side effects.

METHODS

A systematic literature review was conducted on the 29th of November 2021 using PubMed, Scopus and Web of Science databases through the following search strategy: ("Ibogaine" OR "Noribogaine") AND ("SUD" OR "substance use disorder" OR "craving" OR "abstinence" OR "withdrawal" OR "addiction" OR "detoxification") NOT animal NOT review NOT "vitro." The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was followed for data gathering purposes. Research methods were registered on PROSPERO (CRD42021287034).

RESULTS

Thirty-one articles were selected for the systematic revision, and two were considered for analysis. The results were organised according to the type of study: case reports/case series, randomised- controlled trials (RCTs), open-label, survey and observational studies. The main outcomes were related to the anti-addictive effect of ibogaine and its cardiac toxicity. A meta-analysis of side effects was conducted using RevMan 5.4 software, showing a significant risk of developing headaches after ibogaine/noribogaine treatment.

CONCLUSION

The results show some efficacy of ibogaine in the treatment of SUDs, but its cardiotoxicity and mortality are worrying. Further studies are needed to assess its therapeutic efficacy and actual safety.

Psilocybin for Depression: From Credibility to Feasibility, What's Missing?

Psilocybin has been suggested as a promising transdiagnostic treatment strategy for a wide range of psychiatric disorders. Recent findings showed that psychedelic-assisted/"psycholitic" psychotherapy should provide significant and sustained alleviation of depressive symptoms. However, to date, there have been several study limitations (e.g., small sample sizes, blinding, limited follow-up, highly screened treatment populations) and some health/political issues, including practitioners' experience, lack of standardized protocols, psychedelics' legal status, ethical concerns, and potential psychological/psychopathological/medical untoward effects. The focus here is on a range of clinical and methodological issues, also aiming at outlining some possible suggestions. We are confident that newer evidence, more precise protocols, and eventual reclassification policies may allow a better understanding of the real potential of psilocybin as a transdiagnostic therapeutic molecule.

Therapeutic (Sub)stance: Current practice and therapeutic conduct in preparatory sessions in substance-assisted psychotherapy-A systematized review

BACKGROUND

Clinical trials are currently investigating the potential of substance-assisted psychotherapy (SAPT) as treatment for several psychiatric conditions. The potential therapeutic effects of SAPT may be influenced by contextual factors including preparation prior to and integration after the substance-assisted therapy sessions.

AIMS

This systematized review outlines recommendations for current practice in preparatory sessions in SAPT including safety measures and screening procedures, preparation of set and setting, session contents, methods, and roles, prerequisites, and appropriate conduct of therapists.

METHODS

A systematized review of the literature was conducted based on PRISMA guidelines. MEDLINE (OVID), PsycINFO (OVID), and Cochrane Library were searched and clinical trials, treatment manuals, study protocols, case studies, qualitative studies, descriptive studies, theoretical papers, reviews, book chapters, and conference proceedings published until February 1, 2022 were retrieved.

RESULTS

The final synthesis included k = 83 sources. Information about safety measures including screening of participants, set and setting, contextual-, physiological-, and psychological preparation, roles, competencies, prerequisites, and characteristics of the therapists, and the establishment of a therapeutic relationship were summarized and discussed.

CONCLUSION

It is concluded that there is a consensus in the literature about the importance of adequate preparation before the administration of psychoactive substances in SAPT. However, the extent and approaches for these sessions vary across different models and there is a need for timelier and more rigorous qualitative and quantitative investigations assessing different approaches and techniques for the optimal preparation of clients in SAPT.

Where do we go next in antidepressant drug discovery? A new generation of antidepressants: a pivotal role of AMPA receptor potentiation and mGlu2/3 receptor antagonism

INTRODUCTION

Major depressive disorder remains a prevalent world-wide health problem. Currently available antidepressant medications take weeks of dosing, do not produce antidepressant response in all patients, and have undesirable ancillary effects.

AREAS COVERED

The present opinion piece focuses on the major inroads to the creation of new antidepressants. These include N-methyl-D-aspartate (NMDA) receptor antagonists and related compounds like ketamine, psychedelic drugs like psilocybin, and muscarinic receptor antagonists like scopolamine. The preclinical and clinical pharmacological profile of these new-age antidepressant drugs is discussed.

EXPERT OPINION

Preclinical and clinical data have accumulated to predict a next generation of antidepressant medicines. In contrast to the current standard of care antidepressant drugs, these compounds differ in that they demonstrate rapid activity, often after a single dose, and effects that outlive their presence in brain. These compounds also can provide efficacy for treatment-resistant depressed patients. The mechanism of action of these compounds suggests a strong glutamatergic component that involves the facilitation of AMPA receptor function. Antagonism of mGlu2/3 receptors is also relevant to the antidepressant pharmacology of this new class of drugs. Based upon the ongoing efforts to develop these new-age antidepressants, new drug approvals are predicted in the near future.

Arketamine, a new rapid-acting antidepressant: A historical review and future directions

The N-methyl-d-aspartate receptor (NMDAR) antagonist (R,S)-ketamine causes rapid onset and sustained antidepressant actions in treatment-resistant patients with major depressive disorder (MDD) and other psychiatric disorders, such as bipolar disorder and post-traumatic stress disorder. (R,S)-ketamine is a racemic mixture consisting of (R)-ketamine (or arketamine) and (S)-ketamine (or esketamine), with (S)-enantiomer having greater affinity for the NMDAR. In 2019, an esketamine nasal spray by Johnson & Johnson was approved in the USA and Europe for treatment-resistant depression. In contrast, an increasing number of preclinical studies show that arketamine has greater potency and longer-lasting antidepressant-like effects than esketamine in rodents, despite the lower binding affinity of arketamine for the NMDAR. Importantly, the side effects, i.e., psychotomimetic and dissociative effects and abuse liability, of arketamine are less than those of (R,S)-ketamine and esketamine in animals and humans. An open-label study demonstrated the rapid and sustained antidepressant effects of arketamine in treatment-resistant patients with MDD. A phase 2 clinical trial of arketamine in treatment-resistant patients with MDD is underway. This study was designed to review the brief history of the novel antidepressant arketamine, the molecular mechanisms underlying its antidepressant actions, and future directions.

Classic Psychedelics and Human-Animal Relations

Previous research has found associations between classic psychedelic use and nature-relatedness, but the link between classic psychedelic use and human−animal relations remains largely unexplored. Using data representative of the US adult population, with regard to age, sex and ethnicity (N = 2822), this pre-registered study assessed lifetime classic psychedelic use, ego dissolution during respondents’ most intense experience using a classic psychedelic, and three measures related to human−animal relations: speciesism, animal solidarity and desire to help animals. The results showed that lifetime classic psychedelic use was negatively associated with speciesism (β = −0.07, p = 0.002), and positively associated with animal solidarity (β = 0.04, p = 0.041), but no association was found with desire to help animals (β = 0.01, p = 0.542). Ego dissolution during the respondents’ most intense experience using a classic psychedelic was negatively associated with speciesism (β = −0.17, p < 0.001), and positively associated with animal solidarity (β = 0.18, p < 0.001) and desire to help animals (β = 0.10, p = 0.007). The findings indicate that classic psychedelics and ego dissolution may have an impact on human−animal relations. As these results cannot demonstrate causality, however, future studies should use longitudinal research designs to further explore the potential causal link between classic psychedelic use and human−animal relations.