How does ayahuasca work from a psychiatric perspective? Pros and cons of the entheogenic therapy

The current state of ayahuasca research in animal models: A systematic review

RATIONALE

The psychedelic brew ayahuasca is increasingly being investigated for its therapeutic potential. Animal models are essential to investigate the pharmacological effects of ayahuasca since they can control important factors influencing it, such as the set and setting.

OBJECTIVE

Review and summarise data available on ayahuasca research using animal models.

METHODS

We systematically searched five databases (PubMed, Web of Science, EMBASE, LILACS and PsycInfo) for peer-reviewed studies in English, Portuguese or Spanish published up to July 2022. The search strategy included ayahuasca- and animal model-related terms adapted from the SYRCLE search syntax.

RESULTS

We identified 32 studies investigating ayahuasca effects on toxicological, behavioural and (neuro)biological parameters in rodents, primates and zebrafish. Toxicological results show that ayahuasca is safe at ceremonial-based doses but toxic at high doses. Behavioural results indicate an antidepressant effect and a potential to reduce the reward effects of ethanol and amphetamines, while the anxiety-related outcomes are yet inconclusive; also, ayahuasca can influence locomotor activity, highlighting the importance of controlling the analysis for locomotion when using tasks depending on it. Neurobiological results show that ayahuasca affects brain structures involved in memory, emotion and learning and that other neuropathways, besides the serotonergic action, are important in modulating its effects.

CONCLUSIONS

Studies using animal models indicate that ayahuasca is toxicologically safe in ceremonial-comparable doses and indicates a therapeutic potential for depression and substance use disorder while not supporting an anxiolytic effect. Essential gaps in the ayahuasca field can still be sufficed using animal models.

Ayahuasca's therapeutic potential: What we know - and what not

The therapeutic potential of the psychedelic brew ayahuasca has been investigated in preclinical and clinical studies. Currently, the most consistent evidence refers to depression. However, various studies suggest that ayahuasca may comprise therapeutic benefits in other health conditions. This narrative review provides a comprehensive, up-to-date overview of ayahuasca's therapeutic effects in diverse clinical conditions in human (clinical, cross-sectional, observational, and qualitative) and preclinical (animal and in vitro) studies. In addition to summarizing and discussing the most commonly studied conditions, such as depression, anxiety, and substance use disorders (SUD), we also examine less frequently studied psychiatric, neurological, and physical conditions. Moreover, we discuss evidence from epidemiological studies on the impact of regular, long-term ayahuasca use on health and psychosocial outcomes. Overall, evidence for depression and SUD is more consistent, with numerous and diverse studies. However, a growing body of evidence suggests that other conditions equally relevant to public health might be promising targets for ayahuasca's therapeutic effects. This includes preliminary studies indicating potential for grief, eating disorders, posttraumatic stress disorder, personality disorders, Parkinson's and Alzheimer's disease, and severe physical illnesses (e.g., cancer, chronic conditions). Moreover, preliminary evidence in long-term ayahuasca users does not suggest detrimental effects but possible benefits for individual and collective health. In light of the emerging evidence of psychedelic drugs as therapeutic agents, it is essential to further investigate in rigorous designs the therapeutic potential of ayahuasca in conditions other than depression.

Beyond the Psychoactive Effects of Ayahuasca: Cultural and Pharmacological Relevance of Its Emetic and Purging Properties

The herbal preparation ayahuasca has been an important part of ritual and healing practices, deployed to access invisible worlds in several indigenous groups in the Amazon basin and among mestizo populations of South America. The preparation is usually known to be composed of two main plants, Banisteriopsis caapi and Psychotria viridis, which produce both hallucinogenic and potent purging and emetic effects; currently, these are considered its major pharmacological activities. In recent decades, the psychoactive and visionary effect of ayahuasca has been highly sought after by the shamanic tourism community, which led to the popularization of ayahuasca use globally and to a cultural distancing from its traditional cosmological meanings, including that of purging and emesis. Further, the field of ethnobotany and ethnopharmacology has also produced relatively limited data linking the phytochemical diversity of ayahuasca with the different degrees of its purging and emetic versus psychoactive effects. Similarly, scientific interest has also principally addressed the psychological and mental health effects of ayahuasca, overlooking the cultural and pharmacological importance of the purging and emetic activity. The aim of this review is therefore to shed light on the understudied purging and emetic effect of ayahuasca herbal preparation. It firstly focuses on reviewing the cultural relevance of emesis and purging in the context of Amazonian traditions. Secondly, on the basis of the main known phytochemicals described in the ayahuasca formula, a comprehensive pharmacological evaluation of their emetic and purging properties is presented.

The Architecture of Happiness

Happiness is an increasingly prominent topic of interest across academia. However, relatively little attention has been paid to how it is created, especially not in a multidimensional sense. By ‘created’ we do not mean its influencing factors, for which there is extensive research, but how it actually forms in the person. The work that has been done in this arena tends to focus on physiological dynamics, which are certainly part of the puzzle. But they are not the whole picture, with psychological, phenomenological, and socio cultural processes also playing their part. As a result, this paper offers a multidimensional overview of scholarship on the ‘architecture’ of happiness, providing a stimulus for further work into this important topic.

N,N-dimethyltryptamine and Amazonian ayahuasca plant medicine

OBJECTIVE

Reports have indicated possible uses of ayahuasca for the treatment of conditions including depression, addictions, post-traumatic stress disorder, anxiety and specific psychoneuroendocrine immune system pathologies. The article assesses potential ayahuasca and N,N-dimethyltryptamine (DMT) integration with contemporary healthcare. The review also seeks to provide a summary of selected literature regarding the mechanisms of action of DMT and ayahuasca; and assess to what extent the state of research can explain reports of unusual phenomenology.

DESIGN

A narrative review.

RESULTS

Compounds in ayahuasca have been found to bind to serotonergic receptors, glutaminergic receptors, sigma-1 receptors, trace amine-associated receptors, and modulate BDNF expression and the dopaminergic system. Subjective effects are associated with increased delta and theta oscillations in amygdala and hippocampal regions, decreased alpha wave activity in the default mode network, and stimulations of vision-related brain regions particularly in the visual association cortex. Both biological processes and field of consciousness models have been proposed to explain subjective effects of DMT and ayahuasca, however, the evidence supporting the proposed models is not sufficient to make confident conclusions. Ayahuasca plant medicine and DMT represent potentially novel treatment modalities.

CONCLUSIONS

Further research is required to clarify the mechanisms of action and develop treatments which can be made available to the general public. Integration between healthcare research institutions and reputable practitioners in the Amazon is recommended.

Ayahuasca, a potentially rapid acting antidepressant: focus on safety and tolerability

INTRODUCTION

Ayahuasca is a psychedelic brew originally used by indigenous tribes from the Amazon Rainforest and in religious rituals. Pre-clinical and observational studies have demonstrated its possible potential as an antidepressant, and open and placebo-controlled clinical trials corroborated these results. For it to become an approved treatment for depression, its safety and tolerability need to be assessed and documented.

AREAS COVERED

We have gathered data regarding occurrence of adverse events (AEs) in all reported randomized, placebo-controlled trials with healthy and clinical populations involving ayahuasca administration (n = 108 ayahuasca administrations). We systematically categorized these results, recorded their prevalence and discussed the possible mechanisms related to their emergence.

EXPERT OPINION

: There were no reports of serious AEs, indicating a relative safety of ayahuasca administration in controlled settings. Most common AEs related to ayahuasca administration included nausea, vomiting, headaches and transient increases in cardiovascular measurements. Ayahuasca research is still in its infancy, especially concerning the absence of large and robust clinical trials to verify its antidepressant effects. Dose standardization, legal prohibition of the possession of its alkaloids and how traditional communities will be compensated if ayahuasca becomes an approved medicine are the biggest obstacles to overcome for its future use in the therapeutic context.

Ayahuasca blocks ethanol preference in an animal model of dependence and shows no acute toxicity

ETHNOPHARMACOLOGICAL RELEVANCE

Ayahuasca, a psychoactive beverage prepared from Banisteriopsis caapi and Psychotria viridis, is originally used by Amazon-based indigenous and mestizo groups for medicinal and ritualistic purposes. Nowadays, ayahuasca is used in religious and shamanic contexts worldwide, and preliminary evidence from preclinical and observational studies suggests therapeutic effects of ayahuasca for the treatment of substance (including alcohol) use disorders.

AIM OF THE STUDY

To investigate the initial pharmacological profile of ayahuasca and its effects on ethanol rewarding effect using the conditioned place preference (CPP) paradigm in mice.

MATERIALS AND METHODS

Ayahuasca beverage was prepared using extracts of B. caapi and P. viridis, and the concentration of active compounds was assessed through high performance liquid chromatography (HPLC). The following behavioral tests were performed after ayahuasca administration: general pharmacological screening (13, 130, or 1300 mg/kg - intraperitoneally - i.p., and 65, 130, 1300, or 2600 mg/kg - via oral - v.o.); acute toxicity test with elevated doses (2600 mg/kg - i.p., and 5000 mg/kg - v.o.); motor activity, motor coordination, and hexobarbital-induced sleeping time potentiation (250, 500, or 750 mg/kg ayahuasca or vehicle - v.o.). For the CPP test, the animals received ayahuasca (500 mg/kg - v.o.) prior to ethanol (1.8 g/kg - i.p.) or vehicle (control group - i.p.) during conditioning sessions.

RESULTS

Ayahuasca treatment presented no significant effect on motor activity, motor coordination, hexobarbital-induced sleeping latency or total sleeping time, and did not evoke signs of severe acute toxicity at elevated oral doses. Ayahuasca pre-treatment successfully inhibited the ethanol-induced CPP and induced CPP when administered alone.

CONCLUSIONS

Our results indicate that ayahuasca presents a low-risk acute toxicological profile when administered orally, and presents potential pharmacological properties that could contribute to the treatment of alcohol use disorders.

Influence of Context and Setting on the Mental Health and Wellbeing Outcomes of Ayahuasca Drinkers: Results of a Large International Survey

Ayahuasca is a traditional plant decoction containing N,N-dimethyltryptamine (DMT) and various β-carbolines including harmine, harmaline, and tetrahydroharmine, which has been used ceremonially by Amazonian Indigenous groups for healing and spiritual purposes. Use of the brew has now spread far beyond its original context of consumption to North America, Europe, and Australia in neo-shamanic settings as well as Christian syncretic churches. While these groups have established their own rituals and protocols to guide use, it remains unknown the extent to which the use of traditional or non-traditional practices may affect drinkers' acute experiences, and longer term wellbeing and mental health outcomes. Hence, this study aimed to provide the first detailed assessment of associations between ceremony/ritual characteristics, additional support practices, motivations for drinking, and mental health and wellbeing outcomes. The paper uses data from a large cross-sectional study of ayahuasca drinkers in more than 40 countries who had used ayahuasca in various contexts (n = 6,877). It captured detailed information about participant demographics, patterns and history of ayahuasca drinking, the setting of consumption, and ritualistic practices employed. Current mental health status was captured via the Kessler 10 psychological distress scale and the mental health component score of the SF-12 Health Questionnaire, while reported change in prior clinically diagnosed anxiety or depression (n = 1276) was evaluated using a (PGIC) Patient Global Impression of Change tool. Various intermediate outcomes were also assessed including perceived change in psychological wellbeing, number of personal self-insights attained, and subjective spiritual experience measured via the spirituality dimension of the Persisting Effects Questionnaire (PEQ) and Short Index of Mystical Orientation. Regression models identified a range of significant associations between set and setting variables, and intermediate and final mental health and wellbeing outcomes. A generalized structural equation model (GSEM) was then used to verify relationships and associations between endogenous, mediating and final outcome variables concurrently. The present study sheds new light on the influence of ceremonial practices, additional supports and motivations on the therapeutic effects of ayahuasca for mental health and wellbeing, and ways in which such factors can be optimized in naturalistic settings and clinical studies.

Fast Hollow Fiber Liquid-Phase Microextraction as a Greener Alternative for the Determination of N,N-Dimethyltryptamine and Harmala Alkaloids in Human Urine

Ayahuasca tea is an entheogen hallucinogenic beverage used for shamanic and spiritual purposes, prepared by the decoction of different Amazonian plants containing N,N-dimethyltryptamine (DMT) and harmala alkaloids. Since the therapeutic potential of this tea has been broadly studied in recent years, mainly for the treatment of psychiatric disorders, the determination of the ayahuasca tea components in human and animal matrices is of utmost importance. In order to avoid the use of large amounts of toxic solvents, typically employed in traditional sample preparation methods, hollow fiber liquid-phase microextraction (HF-LPME) presents a greener and time-saving alternative. The present study aims to fully develop and apply an HF-LPME method for the determination of DMT, harmine (HRM), harmaline (HRL), and tetrahydroharmine (THH) in human urine samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Fractional factorial and Box–Behnken designs were used to identify and optimize significant method variables. Once optimized, validation has shown a limit of detection (LoD) of 1.0 ng/ml for DMT and 2.0 ng/ml for the harmala alkaloid. The limit of quantification (LoQ) was of 5.0 ng/ml for all analytes. The method has shown to be linear over a concentration range of 5–200 ng/ml (r² ≥ 0.99). Intra/inter-day precision and accuracy met the acceptance criteria at the three quality control (QC) levels studied (15.0, 90.0, and 170.0 ng/ml, n = 6, each). Matrix effect evaluation showed predominant ion enhancement and recovery values were above 80%. Dilution factors of 10- and 20-fold have shown acceptable values of accuracy. Selectivity studies showed no interferences. Analysis of eight authentic samples collected from four subjects proved method feasibility. A simple, time-saving and green alternative for the analysis of DMT and harmala alkaloids in human urine samples was developed, optimized using design of experiments, fully validated and applied to authentic samples.