Modalities of the psychedelic experience: Microclimates of set and setting in hallucinogen research and culture

Mid-20th-century American research on psychedelics evinced a stunning diversity of interpretations of hallucinogenic effects. While some researchers viewed psychedelics as invaluable tools for psychotherapy, others persisted in treating them as psychosis-inducing agents. As some groups considered psychedelics as catalysts for artistic creativity, others investigated their potential use as psychochemical weapons in the battlefield, or conversely as tools for spiritual ecstasy and revelation. This bewildering array of perceptions regarding the nature of hallucinogenic effects led to stark contrasts in the contexts (set and setting) of psychedelic research and experimentation, leading to wildly divergent outcomes and reports on the effects of the drugs, and strident disagreements between the actors in the field. Examining this remarkable historical moment of epistemological unclarity regarding psychedelics and their effects, this article describes how distinct scientific and cultural trends and moments of mid-20th-century America contributed to the creation of diverse microclimates of set and setting that reproduced investigator beliefs and attitudes and brought about a beguiling Pygmalion effect that left researchers befuddled and perplexed. I propose the concept of psychedelic modality to describe how distinct sociocultural microclimates lead to thematic aggregates in which distinct types of expectations, intentions as well as physical, social, and cultural environments all tend to cluster, producing characteristic outcomes and results. By exploring the historical context and consequences of the emergence of seven psychedelic modalities (psychotomimetic, military, psychotherapeutic, spiritual, artistic-creative, tech-innovative, and political) in mid-20th-century America, this article outlines the varieties of psychedelic experiences in their relationship with culture at large, and subcultures in particular.

The socialization of hallucinations: Cultural priors, social interactions, and contextual factors in the use of psychedelics

The effects of so-called "psychedelic" or "hallucinogenic" substances are known for their strong conditionality on context. While the so-called culturalist approach to the study of hallucinations has won the favor of anthropologists, the vectors by which the features of visual and auditory imagery are structured by social context have been so far little explored. Using ethnographic data collected in a shamanic center of the Peruvian Amazon and an anthropological approach dialoguing with phenomenology and recent models of social cognition of Bayesian inspiration, I aim to shed light on the nature of these dynamics through an approach I call the "socialization of hallucinations." Distinguishing two levels of socialization of hallucinations, I argue that cultural background and social interactions organize the relationship not only to the hallucinogenic experience, but also to its very phenomenological content. I account for the underpinnings of the socialization of hallucinations proposing such candidate factors as the education of attention, the categorization of perceptions, and the shaping of emotions and expectations. Considering psychedelic experiences in the light of their noetic properties and cognitive penetrability debates, I show that they are powerful vectors of cultural transmission. I question the ethical stakes of this claim, at a time when the use of psychedelics is becoming increasingly popular in the global North. I finally emphasize the importance of better understanding the extrapharmacological factors of the psychedelic experience and its subjective implications, and sketch out the basis for an interdisciplinary methodology in order to do so.

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.

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

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

A Dose of Creativity: An Integrative Review of the Effects of Serotonergic Psychedelics on Creativity

This integrative review was conducted to summarize the knowledge pertaining to the effects that serotonergic psychedelics can have on creativity, a multi-dimensional construct referring to the ability to produce original and valuable artifacts. Psychedelics, which have long been hailed as substances that can enhance the creative process in their users, have experienced a recent resurgence in research, allowing the opportunity to better understand this relationship. To this end, I reviewed literature which attempted to study the effects of serotonergic psychedelics on creativity through psychometric methods. A total of eleven studies were reviewed, with four psychedelic compounds represented. Every study assessed components and subcomponents of divergent and convergent thinking, with only one instance of product assessment. Results suggest that convergent thinking may increase during the post-acute phases of the drugs' intake, fostering the capacity for development of previously generated ideas. However, this evidence may be circumstantial based on the low number of studies available, small sample sizes, overall lack of randomized controlled trials, and significant methodological limitations throughout most studies. Potential mechanisms underlying these effects are discussed, along with the current state of the research and implications for future studies.

Effects of ayahuasca on the endocannabinoid system of healthy volunteers and in volunteers with social anxiety disorder: Results from two pilot, proof-of-concept, randomized, placebo-controlled trials

OBJECTIVE

To assess endocannabinoid (anandamide, AEA; 2-arachidonoylglycerol, 2-AG) plasma levels in healthy volunteers and in volunteers with social anxiety disorder (SAD) after a single oral dose of ayahuasca or placebo.

METHODS

Post hoc analysis of endocannabinoid plasma levels (baseline, 90 and 240 min after drug intake) from two parallel-group, randomized, placebo-controlled trials. In Study 1, 20 healthy volunteers ingested ayahuasca (average 1.58 mg/ml dimethyltryptamine (DMT)) or placebo, and in Study 2, 17 volunteers with SAD received ayahuasca (average 0.680 mg/ml DMT) or placebo.

RESULTS

A significant difference was observed in AEA concentrations in Study 2 after ayahuasca intake (Χ² (2) = 6.5, p = 0.03, Friedman test), and near significant differences (increases) were observed between baseline and 90 (Z = 0, p = 0.06, Wilcoxon test) and 240 (Z = 10, p = 0.06) minutes after ayahuasca intake.

CONCLUSIONS

Although our findings suggest that ayahuasca could modulate AEA levels in SAD patients, the high interindividual variability in both trials and the small samples preclude definitive conclusions. More research with larger samples is needed to better understand the effects of ayahuasca and other hallucinogens in the endocannabinoid system.

The Therapeutic Potential of Psychedelic-assisted Therapies for Symptom Control in Patients Diagnosed With Serious Illness: A Systematic Review

CONTEXT

People affected by serious illness usually experience suffering in its various dimensions, not only in the physical but also in the psychosocial and spiritual aspects. The interest in psychedelic-assisted therapies as a potential new therapeutic modality has increased since evidence suggests a significant impact of their use on the outcomes of patients with serious illness.

OBJECTIVES

To systematically review the available evidence on the effects of psychedelic-assisted therapies for symptom control in patients diagnosed with serious illness.

METHODS

The protocol of this systematic review has been prepared according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines. This review included randomized and non-randomized controlled trials published in peer-reviewed scientific journals. A comprehensive search for studies was carried out in the main scientific databases, including Web of Science, Scopus, Cochrane Library, PsycINFO, PubMed, CINAHL, and EMBASE. There were no limitations regarding the year or language of publication.

RESULTS

The sample was composed of 20 studies. The results suggest positive effects of psychedelic-assisted therapies for symptom control in patients diagnosed with serious illness, with considerable safety of use. Most studies have been conducted with lysergic acid diethylamide, psilocybin, and N,N-dipropyltryptamine in cancer patients. The adverse effects reported were of physical and/or psychological nature and of mild to moderate intensity, transient, and self-resolutive.

CONCLUSION

The evaluated evidence suggests positive effects of psychedelic-assisted therapies for symptom control in patients diagnosed with serious illness, especially regarding symptoms of psychological and spiritual nature.

Systematic Review of Psychometric Instruments Used in Research with Psychedelics

There has been a revival of research that studies the subjective effects of psychedelic drugs on humans. Areas of health science have been studying their possible therapeutic benefits, and psychological measurement instruments are being developed as the studies progress. However, these instruments currently suffer criticism regarding their number and evidence of psychometric quality. This study aims to review which psychometric instruments are available to assess subjective states induced by psychedelics. We systematically searched five databases (Web of Science, Academic Search Premier, EMBASE, CINAHL and PubMed) using psychometrics and psychedelics related terms identifying studies published from 1990 to 2021. Of 857 articles generated from the systematic-search, fifteen met our criteria and were included in the review, evaluating nine instruments: MEQ, 5D-ASC, HRS, PSI, EDI, CEQ, EBI, EDI and PIQ. Eight dealing with phenomenological aspects of the psychedelic experience and one as a screening tool for psychotic or manic episode. The purpose of each instrument, the number of items in each version, the type of scale and their elaboration process were described. The number of instruments used in psychedelic research is growing steadily, but there are still many other parts of the psychedelic experience that lack measurement.

Loss of Consciousness and Visual Hallucinations Related to 5-MeO-DALT Intake, a Case Report Confirmed by Toxicological Analyses

5-MeO-DALT or 5-methoxy-N,N-diallyltryptamine is a derivative of tryptamines, consumed for its hallucinogenic and entheogenic effects. We report the case of a 46-year-old-man, presenting with a brief loss of consciousness and visual hallucinations, after the consumption of three 5-MeO-DALT tablets bought online. Liquid chromatography coupled to tandem mass spectrometry method (LC-MS/MS) was performed, and 5-Meo-DALT was quantified in both the tablets (32,5 mg per tablet, 11% of purity) and the patient's plasma (7 ng/ml - 8 hours between the consumption and the blood sample). 5-MeO-DALT poisonings are rarely described. Given the broad availability of these products, it is important that emergency department physicians and clinical toxicologists do not overlook the possibility of the ingestion of recreational tryptamines, especially since they are not detected by most routine toxicological screening.

In vitro assays for the functional characterization of (psychedelic) substances at the serotonin receptor 5-HT2A R

Serotonergic psychedelics are substances that induce alterations in mood, perception, and thought, and have the activation of serotonin (5-HT) 2A receptors (5-HT_2A Rs) as a main pharmacological mechanism. Besides their appearance on the (illicit) drug market, e.g. as new psychoactive substances, their potential therapeutic application is increasingly explored. This group of substances demonstrates a broad structural variety, leading to insufficiently described structure-activity relationships, hence illustrating the need for better functional characterization. This review therefore elaborates on the in vitro molecular techniques that have been used the most abundantly for the characterization of (psychedelic) 5-HT_2A R agonists. More specifically, this review covers assays to monitor the canonical G protein signaling pathway (e.g. measuring G protein recruitment/activation, inositol phosphate accumulation, or Ca²⁺ mobilization), assays to monitor non-canonical G protein signaling (such as arachidonic acid release), assays to monitor β-arrestin recruitment or signaling, and assays to monitor receptor conformational changes. In particular, focus lies on the mechanism behind the techniques, and the specific advantages and challenges that are associated with these. Additionally, several variables are discussed that one should consider when attempting to compare functional outcomes from different studies, both linked to the specific assay mechanism and linked to its specific execution, as these may heavily impact the assay outcome.

From Underground to Mainstream: Establishing a Medical Lexicon for Psychedelic Therapy

We argue that non-stigmatizing and precise terminology grounded in the medical model will advance both the science and public acceptance of psychedelics. Researchers and clinicians should take care to distinguish between medical, recreational, and spiritual uses to set clear boundaries and expectations for patients. Ethically fraught or stigmatizing terms should be replaced with terminology that is medically and scientifically descriptive and accurate. A medicalized linguistic framework around psychedelics will potentially yield benefits and mitigate risks. Replacing colloquial names with scientific names for medicines and therapies may help correct misconceptions about psychedelics commonly held by both professionals and the public. A harmonized medical lexicon will also provide a common language for important instances of communication-such as the informed consent process-between professionals and participants. Our recommendations draw upon communications research in addiction medicine and aim to encourage the development, acceptance, and implementation of non-stigmatizing terminology in psychedelic research and treatment.

Lower-dose psycholytic therapy - A neglected approach

Lysergic acid diethylamide (LSD) and similar psychoactive drugs have been used in psychotherapy since 1949, when the first clinical study with lower-dose LSD showed therapeutically relevant effects. This caused an intense interest among psychotherapists and researchers, alike, on an international scale. In 1960, the use of serial lower-dose LSD/psilocybin sessions in a psychoanalytical framework, which was dominant at the time, was named "psycholytic therapy". Psycholytic therapy was usually conducted in clinical environments, on both an inpatient and outpatient basis. Psycholytic therapy was developed and established over a 15-year period on the European continent, where it was used at 30 clinical treatment centers and by more than 100 outpatient psychotherapists. Psycholytic approaches were employed minimally in North America, where the psychedelic approach (use of one or two high-dose sessions for "personality-transforming mystical experiences") became the dominant method in use. The leading figure in psycholytic therapy was Professor Hanscarl Leuner in Germany, who laid the ground with his uniquely fine grained analysis of the LSD reaction in a 1962 monograph. He was central in establishing and distributing psycholytic therapy in Europe and abroad. The article provides comprehensive background information and outlines the essential features of psycholytic therapy. Evidence for the efficacy of psycholytic therapy is reviewed and a case for the inclusion of the psycholytic approach in the field of substance-assisted psychotherapy is made.

Psychedelic Therapy's Transdiagnostic Effects: A Research Domain Criteria (RDoC) Perspective

Accumulating clinical evidence shows that psychedelic therapy, by synergistically combining psychopharmacology and psychological support, offers a promising transdiagnostic treatment strategy for a range of disorders with restricted and/or maladaptive habitual patterns of emotion, cognition and behavior, notably, depression (MDD), treatment resistant depression (TRD) and addiction disorders, but perhaps also anxiety disorders, obsessive-compulsive disorder (OCD), Post-Traumatic Stress Disorder (PTSD) and eating disorders. Despite the emergent transdiagnostic evidence, the specific clinical dimensions that psychedelics are efficacious for, and associated underlying neurobiological pathways, remain to be well-characterized. To this end, this review focuses on pre-clinical and clinical evidence of the acute and sustained therapeutic potential of psychedelic therapy in the context of a transdiagnostic dimensional systems framework. Focusing on the Research Domain Criteria (RDoC) as a template, we will describe the multimodal mechanisms underlying the transdiagnostic therapeutic effects of psychedelic therapy, traversing molecular, cellular and network levels. These levels will be mapped to the RDoC constructs of negative and positive valence systems, arousal regulation, social processing, cognitive and sensorimotor systems. In summarizing this literature and framing it transdiagnostically, we hope we can assist the field in moving toward a mechanistic understanding of how psychedelics work for patients and eventually toward a precise-personalized psychedelic therapy paradigm.

Molecular targets of psychedelic-induced plasticity

Psychedelic research across different disciplines and biological levels is growing at a remarkably fast pace. In the prospect of a psychedelic drug becoming again an approved treatment, much of these efforts have been oriented toward exploring the relationship between the actual psychedelic effects and those manifestations of therapeutic interest. Considering the central role of the serotonin 5-HT_2A receptor in the distinct effects of psychedelics in human psyche, neuropharmacology sits at the center of this debate and exploratory continuum. Here we discuss some of the most recent findings in human studies and contextualize them considering previous preclinical models studying phenomena related to synaptic plasticity. A special emphasis is placed on knowledge gaps, challenges, and limitations to evaluate the underpinnings of psychedelics' potential antidepressant action.

Prolonged epigenomic and synaptic plasticity alterations following single exposure to a psychedelic in mice

Clinical evidence suggests that rapid and sustained antidepressant action can be attained with a single exposure to psychedelics. However, the biological substrates and key mediators of psychedelics' enduring action remain unknown. Here, we show that a single administration of the psychedelic DOI produces fast-acting effects on frontal cortex dendritic spine structure and acceleration of fear extinction via the 5-HT2A receptor. Additionally, a single dose of DOI leads to changes in chromatin organization, particularly at enhancer regions of genes involved in synaptic assembly that stretch for days after the psychedelic exposure. These DOI-induced alterations in the neuronal epigenome overlap with genetic loci associated with schizophrenia, depression, and attention deficit hyperactivity disorder. Together, these data support that epigenomic-driven changes in synaptic plasticity sustain psychedelics' long-lasting antidepressant action but also warn about potential substrate overlap with genetic risks for certain psychiatric conditions.

The Kappa Opioid Receptor and the Sleep of Reason: Cortico-Subcortical Imbalance Following Salvinorin-A

BACKGROUND

The mechanisms through which kappa opioid receptor (KOR) agonists induce psychotomimetic effects are largely unknown, although the modulation of this receptor has attracted attention for its clinical use. In this work, we characterize the neuropharmacological effects of salvinorin-A, a highly selective KOR agonist.

METHODS

Changes in multimodal electroencephalography, single-photon emission computed tomography, and subjective effects following the acute administration of salvinorin-A are reported. The study included 2 sub-studies that employed a double-blind, crossover, randomized, placebo-controlled design.

RESULTS

The electroencephalography measures showed a marked increase in delta and gamma waves and a decrease in alpha waves while subjects were under the effect of salvinorin-A. Regarding single-photon emission computed tomography measures, significant decreases in regional cerebral blood flow were detected in multiple regions of the frontal, temporal, parietal, and occipital cortices. Significant regional cerebral blood flow increases were observed in some regions of the medial temporal lobe, including the amygdala, the hippocampal gyrus, and the cerebellum. The pattern of subjective effects induced by salvinorin-A was similar to those observed in relation to other psychotomimetic drugs but with an evidently dissociative nature. No dysphoric effects were reported.

CONCLUSION

The salvinorin-A-mediated KOR agonism induced dramatic psychotomimetic effects along with a generalized decrease in cerebral blood flow and electric activity within the cerebral cortex.

Psychedelic-assisted therapy for functional neurological disorders: A theoretical framework and review of prior reports

Functional neurological disorders (FNDs), which are sometimes also referred to as psychogenic neurological disorders or conversion disorder, are common disabling neuropsychiatric disorders with limited treatment options. FNDs can present with sensory and/or motor symptoms, and, though they may mimic other neurological conditions, they are thought to occur via mechanisms other than those related to identifiable structural neuropathology and, in many cases, appear to be triggered and sustained by recognizable psychological factors. There is intriguing preliminary evidence to support the use of psychedelic‐assisted therapy in a growing number of psychiatric illnesses, including FNDs. We review the theoretical arguments for and against exploring psychedelic‐assisted therapy as a treatment for FNDs. We also provide an in‐depth discussion of prior published cases detailing the use of psychedelics for psychosomatic conditions, analyzing therapeutic outcomes from a contemporary neuroscientific vantage as informed by several recent neuroimaging studies on psychedelics and FNDs.

Moral Psychopharmacology Needs Moral Inquiry: The Case of Psychedelics

The revival of psychedelic research coincided and more recently conjoined with psychopharmacological research on how drugs affect moral judgments and behaviors. This article makes the case for a moral psychopharmacology of psychedelics that examines whether psychedelics serve as non-specific amplifiers that enable subjects to (re-)connect with their values, or whether they promote specific moral-political orientations such as liberal and anti-authoritarian views, as recent psychopharmacological studies suggest. This question gains urgency from the fact that the return of psychedelics from counterculture and underground laboratories to mainstream science and society has been accompanied by a diversification of their users and uses. We propose bringing the pharmacological and neuroscientific literature into a conversation with historical and anthropological scholarship documenting the full spectrum of moral and political views associated with the uses of psychedelics. This paper sheds new light on the cultural plasticity of drug action and has implications for the design of psychedelic pharmacopsychotherapies. It also raises the question of whether other classes of psychoactive drugs have an equally rich moral and political life.

Identification of 2C-B in Hair by UHPLC-HRMS/MS. A Real Forensic Case

The analysis of drugs of abuse in hair and other biological matrices of forensic interest requires great selectivity and sensitivity. This has been traditionally achieved through target analysis, using one or more analytical methods that include different preanalytical stages, and more complex procedures followed by toxicological laboratories. There is no exception with 2C-series drugs, such as 2C-B, a new psychoactive substance (NPS), which use has emerged and significantly increased, year by year, in the last decades. Continuously new analytical methods are required to selectively detect and identify these new marketed substances at very low concentrations. In this case report, one former case of a polydrug consumer (charged of a crime against public health in Spain) was reanalyzed in hair matrix. In this reanalysis, 2C-B has been positively detected and identified using liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS/MS). The most selective analytical UHPLC-HRMS/MS method alongside a universal and simpler pretreatment methodology has opened up more possibilities for the detection of substances of different chemical structure and optimization of different HRMS/MS detection approaches allowing the identification of 2-CB in the hair of a real forensic case.

Predicting changes in substance use following psychedelic experiences: natural language processing of psychedelic session narratives

Background: Experiences with psychedelic drugs, such as psilocybin or lysergic acid diethylamide (LSD), are sometimes followed by changes in patterns of tobacco, opioid, and alcohol consumption. But, the specific characteristics of psychedelic experiences that lead to changes in drug consumption are unknown.Objective: Determine whether quantitative descriptions of psychedelic experiences derived using Natural Language Processing (NLP) would allow us to predict who would quit or reduce using drugs following a psychedelic experience.Methods: We recruited 1141 individuals (247 female, 894 male) from online social media platforms who reported quitting or reducing using alcohol, cannabis, opioids, or stimulants following a psychedelic experience to provide a verbal narrative of the psychedelic experience they attributed as leading to their reduction in drug use. We used NLP to derive topic models that quantitatively described each participant's psychedelic experience narrative. We then used the vector descriptions of each participant's psychedelic experience narrative as input into three different supervised machine learning algorithms to predict long-term drug reduction outcomes.Results: We found that the topic models derived through NLP led to quantitative descriptions of participant narratives that differed across participants when grouped by the drug class quit as well as the long-term quit/reduction outcomes. Additionally, all three machine learning algorithms led to similar prediction accuracy (~65%, CI = ±0.21%) for long-term quit/reduction outcomes.Conclusions: Using machine learning to analyze written reports of psychedelic experiences may allow for accurate prediction of quit outcomes and what drug is quit or reduced within psychedelic therapy.

Psychedelic-Assisted Therapy: Emerging Treatments in Mental Health Disorders

Psychedelics are a class of psychoactive substances that were studied extensively between 1943 and 1970 as potential therapies for treating a host of mental health disorders, including addiction. Despite promising early results, U.S. psychedelic research was halted in the early 1970s with the enactment of the Controlled Substances Act. As the field of psychedelic-assisted therapy develops, nurses can decide the role they will play in the continuing clinical and scholarly research of these substances, which may soon be used in controlled settings to treat some of the most widespread mental health disorders. To prepare for this task, this article proposes that nurses * become familiar with the history, relevant language, and scientific findings related to the field of psychedelic research. * learn about existing psychedelic-assisted therapy and research resources. * examine their thoughts, judgments, and opinions about therapeutic psychedelic use. * consider the potential role of nursing in psychedelic-assisted therapies going forward.

Set and Setting in the Santo Daime

Set and setting is a fundamental concept in the field of psychedelic drug research, which points to the profound dependence of psychedelic effects on psychological, social, and cultural factors. Santo Daime is a Brazilian religion that makes elaborate use of ordering principles, techniques, and symbology to shape and direct the effects of the hallucinogenic brew ayahuasca. This paper systematically explores the tapestry of, inter alia, symbolic, social, cultural, psychological, aesthetic and musical elements that participate in the shaping of the psychedelic experience in the context of the Santo Daime ayahuasca religion. The methodically rich under the hood description of the mechanics of entheogenic initiation within the Santo Daime tradition provides a template for future studies of the role of context in psychedelic experimentation.

Molecular and Functional Imaging Studies of Psychedelic Drug Action in Animals and Humans

Hallucinogens are a loosely defined group of compounds including LSD, N,N-dimethyltryptamines, mescaline, psilocybin/psilocin, and 2,5-dimethoxy-4-methamphetamine (DOM), which can evoke intense visual and emotional experiences. We are witnessing a renaissance of research interest in hallucinogens, driven by increasing awareness of their psychotherapeutic potential. As such, we now present a narrative review of the literature on hallucinogen binding in vitro and ex vivo, and the various molecular imaging studies with positron emission tomography (PET) or single photon emission computer tomography (SPECT). In general, molecular imaging can depict the uptake and binding distribution of labelled hallucinogenic compounds or their congeners in the brain, as was shown in an early PET study with N1-([11C]-methyl)-2-bromo-LSD ([11C]-MBL); displacement with the non-radioactive competitor ketanserin confirmed that the majority of [11C]-MBL specific binding was to serotonin 5-HT2A receptors. However, interactions at serotonin 5HT1A and other classes of receptors and pleotropic effects on second messenger pathways may contribute to the particular experiential phenomenologies of LSD and other hallucinogenic compounds. Other salient aspects of hallucinogen action include permeability to the blood-brain barrier, the rates of metabolism and elimination, and the formation of active metabolites. Despite the maturation of radiochemistry and molecular imaging in recent years, there has been only a handful of PET or SPECT studies of radiolabeled hallucinogens, most recently using the 5-HT2A/2C agonist N-(2[11CH3O]-methoxybenzyl)-2,5-dimethoxy- 4-bromophenethylamine ([11C]Cimbi-36). In addition to PET studies of target engagement at neuroreceptors and transporters, there is a small number of studies on the effects of hallucinogenic compounds on cerebral perfusion ([15O]-water) or metabolism ([18F]-fluorodeoxyglucose/FDG). There remains considerable scope for basic imaging research on the sites of interaction of hallucinogens and their cerebrometabolic effects; we expect that hybrid imaging with PET in conjunction with functional magnetic resonance imaging (fMRI) should provide especially useful for the next phase of this research.

Qualitative and Quantitative Analysis of Tryptamines in the Poison of Incilius alvarius (Amphibia: Bufonidae)

Rising numbers of psychoactive tryptamine derivatives have become available on the drug market over the last decade, making these naturally occurring or synthetically manufactured compounds highly relevant for forensic analysis. One of these compounds is 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), a constituent of the dried poison of Incilius alvarius (Colorado River toad) which has a history of ritual and/or recreational use. Still, comprehensive and validated qualitative as well as quantitative analytical data on the psychoactive components of this poison are scarce. In this study samples of the poison of Incilius alvarius were collected from live toads in the Sonoran Desert, Arizona (USA) and analyzed with a set of complementary methods. Acetone/water (70/30, v/v) proved to be the solvent of choice for the extraction of tryptamine derivatives. Trace compounds were enriched and overload with 5-MeO-DMT was prevented by chromatographic separation of 5-MeO-DMT prior to qualitative analysis. The method for quantification was validated. Applying attenuated total reflection-Fourier transform infrared spectroscopy to samples of the poison, 5-MeO-DMT was identified as the main tryptamine by comparison to the reference spectrum. The combined evaluation of analytical data gained from gas chromatography-mass spectrometry (GC-MS), liquid chromatography-quadrupole time-of-flight high resolution MS (HPLC-qToF-HRMS), and HPLC-MS/MS confirmed the presence of 5-MeO-DMT, 5-MeO-N-methyltryptamine, 5-MeO-tryptamine, 5-MeO-tryptophol, 2-(5-methoxy-1H-indol-3-yl)-acetic-acid (5-MIAA), 5-HO-N-methyltryptamine, bufotenin, DMT, and tryptophan. For the first time, 5-MeO-tryptamine and two positional isomers of indole-substituted HO-MeO-DMT were detected in the poison of Incilius alvarius. The tryptamine present in the highest concentrations was 5-MeO-DMT (mean ± standard deviation: 410,000 ± 30,000 µg/g). Mean concentrations of 5-MeO-tryptamine (490 ± 260 µg/g), 5-HO-N-methyltryptamine (270 ± 120 µg/g), bufotenin (2,800 ± 1,900 µg/g), and DMT (250 ± 80 µg/g), showed a relatively high variability between individual samples. The comprehensive analytical reference data of Incilius alvarius poison presented here might prove useful for forensic chemists.