Ayahuasca: Pharmacology, neuroscience and therapeutic potential

Ayahuasca reverses ischemic stroke-induced neuroinflammation and oxidative stress

BACKGROUND

Ischemic stroke is a leading cause of death and disability worldwide. Survivors face disability and psychiatric sequelae resulting from ischemia-induced cell death and associated neuroinflammation, and oxidative stress. Herbal medicines have been shown to elicit neuroprotective effects following stroke due to their anti-inflammatory and antioxidant effects. Preliminary evidence suggests that Ayahuasca (AYA), a decoction made from the vine Banisteriopsis caapi containing β-carbolines and the shrub Psychotria viridis containing N, N-Dimethyltryptamine, might attenuate ischemia-induced neuroinflammation and oxidative stress. Therefore, in this study we investigated the putative protective effects of AYA in the middle cerebral artery occlusion (MCAO) model of ischemic stroke.

METHODS

Wistar rats were subjected to the MCAO stroke model or sham surgery on day 0. After 24-h, rats were treated for three days with AYA (2 and 4 mL/kg, gavage) or saline. Neurological score was assessed for 72-h post-stroke. Rats were tested in the elevated plus maze, open field, and novel object recognition tests to assess locomotion, anxiety-like behavior, and recognition memory. Interleukin (IL)-6, IL-10 myeloperoxidase (MPO) activity, and the nitrite/nitrate (N/N) concentrations were determined in the prefrontal cortex (PFC), hippocampus (HPC), hypothalamus (HYP) and cortex. as markers of inflammation. Oxidative stress was quantified in the same brain areas as measured by the levels of thiobarbituric acid reactive species (TBARS), protein carbonylation, and superoxide dismutase (SOD), and catalase (CAT) activity. Mitochondrial metabolism was assessed quantifying the activity of complex 1(CI), CII, citrate synthase (CS), succinate dehydrogenase (SDH), and creatine kinase (CK).

RESULTS

No differences were observed regarding neurological deficits, locomotion, anxiety-like behavior, and recognition memory. However, AYA reversed the stroke-induced increase in IL-6 levels in the PFC and the HPC, IL-10 in the PFC, HPC, and HYP, MPO activity in the PFC, and N/N concentration and CAT activity in the HYP. Moreover, AYA decreased TBARS levels in the PFC and HPC and brain-derived neurotrophic factor (BDNF) in the PFC, and increased SOD activity in the cortex. Lastly, AYA increased CI activity in the HPC and cortex and decreased SDH and CK activity in the HPC.

CONCLUSION

AYA administration following ischemic stroke modulates oxidative stress and neuroinflammation in the PFC, HPC, and HYP. Despite no significant improvements in neurological or behavioral scores, these molecular changes suggest a neuroprotective role of AYA. Future studies should explore the timing of AYA treatment and putative long-term effects on functional recovery, as well as its potential in other brain regions critical for cognitive and motor functions.

Exploring DMT: Endogenous role and therapeutic potential

N,N-Dimethyltryptamine (DMT) is a naturally occurring amine and psychedelic compound, found in plants, animals, and humans. While initial studies reported only trace amounts of DMT in mammalian brains, recent findings have identified alternative methylation pathways and DMT levels comparable to classical neurotransmitters in rodent brains, calling for a re-evaluation of its biological role and exploration of this inconsistency. This study evaluated DMT's biosynthetic pathways, focusing on indolethylamine N-methyltransferase (INMT) and its isoforms, and possible regulatory mechanisms, including alternative routes of synthesis and how physiological conditions, such as stress and hypoxia influence DMT levels. This review considers the impact of endogenous regulatory factors on DMT synthesis and degradation, particularly under conditions affecting monoamine oxidase (MAO) efficiency and activity. We also examined DMT's potential roles in various physiological processes, including neuroplasticity and neurogenesis, mitochondrial homeostasis, immunomodulation, and protection against hypoxia and oxidative stress. DMT's lipophilic properties allow it to cross cell membranes and activate intracellular 5-HT2A receptors, contributing to its role in neuroplasticity. This suggests DMT may act as an endogenous ligand for intracellular receptors, highlighting its broader biological significance beyond traditional receptor pathways. The widespread evolutionary presence of DMT's biosynthetic pathways across diverse species suggests it may play essential roles in various developmental stages and cellular adaptation to environmental challenges, highlighting the neurobiological significance of DMT and its potential clinical applications. We propose further research to explore the role of endogenous DMT, particularly as a potential neurotransmitter.

Ayahuasca Pretreatment Prevents Sepsis-Induced Anxiety-Like Behavior, Neuroinflammation, and Oxidative Stress, and Increases Brain-Derived Neurotrophic Factor

The psychoactive decoction Ayahuasca (AYA) used for therapeutic and religious purposes by indigenous groups and peoples from Amazonian regions produces anti-inflammatory and neuroprotective effects. Thus, it may be useful to attenuate the neuroinflammation and related anxiety- and depressive-like symptoms elicited by inflammatory insults such as sepsis. Rats were pretreated for 3 days with different doses of AYA. Twenty-four hours after, cecal ligation and puncture (CLP) was performed. On days 1-4, post-CLP behavioral tests to assess anxiety-like behavior were performed. After 24-h, neuroinflammation, oxidative stress, myeloperoxidase activity, and mitochondrial metabolism were assessed in the prefrontal cortex (PFC), hippocampus (HP), and cortex. AYA pretreatment increased the time spent in the open arms of the elevated plus maze and prevented the sepsis-induced hyper-grooming and -rearing behavior, suggesting an anxiolytic effect. AYA pretreatment increased the levels of the anti-inflammatory interleukin 4, in the PFC and the cortex, and brain-derived neurotrophic factor in the cortex. Moreover, AYA pretreatment increased myeloperoxidase activity in the PFC and the HP and decreased nitrite/nitrate concentration in the PFC, HP, and cortex of septic rats, suggesting enhanced neutrophil activation and decreased nitric oxide signaling. Furthermore, AYA pretreatment prevented lipid peroxidation in the PFC, HP, and cortex of septic rats as measured by decreased levels of thiobarbituric acid reactive substances. Levels of protein carbonyls and activity of superoxide dismutase, citrate synthase, succinate dehydrogenase, and mitochondrial respiratory chain were not affected. Together, AYA represents a promising approach to prevent sepsis-induced neuroinflammatory and oxidative stress and associated anxiety-like symptoms.

Ayahuasca Retreats: The Role of Awe and Mystical Experiences in Well-Being

Research on the positive psychological effects of psychedelics has surged since the early 2000s, particularly regarding increased well-being. Studies have demonstrated how psychedelic-occasioned mystical experiences play a key role in their positive effects, which has prompted an interest in the emotion of awe in the psychedelic context due to its similar phenomenology and associated benefits. This study examined 60 individuals following their visitation to at least one ayahuasca retreat in a country where ayahuasca use was legal or retreats are approved to use ayahuasca, hypothesizing that not only high levels of awe but mystical experiences characterized by high levels of awe would be significantly associated with higher well-being. Neither hypothesis was supported: higher levels of mystical experience with lower perceived vastness, a facet of awe, was significantly associated with higher well-being, possibly highlighting the synergistic relationship between mystical experiences and perceived vastness on well-being. The study has implications for future research, particularly in terms of understanding how the perceived vastness of a person's psychedelic experience may be modulated to mitigate distress and foster well-being.

A prospective ecological momentary assessment study of an ayahuasca retreat: exploring the salutary impact of acute psychedelic experiences on subacute affect and mindfulness skills in daily life

RATIONALE

To examine the acute effects of ayahuasca use and their relationship to sub-acute changes in affect and mindfulness in a non-clinical sample, addressing the need for a better understanding of ayahuasca's immediate and short-term impacts as interest in its use grows.

OBJECTIVES

Using prospective ecological assessment, this study investigates how ayahuasca used at a 4-day retreat affects positive/negative affect and mindfulness skills in daily living compared to pre-retreat. Additionally, we explore acute psychedelic experiences during the ayahuasca retreat, assessed retrospectively 1-2 days post-retreat, as potential mechanisms for theorized effects in daily living post-retreat.

METHODS

Thirty-six participants reported positive/negative affect and mindfulness skills three times daily for 5 days before and after the retreat. Baseline assessments included lifetime psychedelic experience, and post-retreat assessments covered acute ayahuasca experiences. Mixed-effect linear models were used to analyze the data.

RESULTS

Post-retreat, we observed reduced negative affect, increased positive affect, and enhanced mindfulness skills in daily living. Ayahuasca-induced acute experiences, such as time/space transcendence, emotional breakthrough and challenging experiences predicted greater subacute positive affect. Notably, none of these experiences were linked to subacute improvements in negative affect or mindfulness. No participants showed clinically significant adverse responses post-retreat, and only 5.5% exhibited some degree of potentially clinically significant deterioration in affect.

CONCLUSIONS

Ayahuasca use may lead to improvement in mood and mindfulness skills, and key acute psychedelic experiences induced by ayahuasca may be important to some of these salutary effects, positive affect in particular.

Examining the pharmacokinetic and pharmacodynamic interaction of N,N-dimethyltryptamine and harmine in healthy volunteers: Α factorial dose-escalation study

Ayahuasca, a traditional psychoactive Amazonian brew, usually contains N,N-dimethyltryptamine (DMT) and β-carboline (harmine, harmaline, tetrahydroharmine) monoamine oxidase inhibitors. However, the pharmacological interactions between these compounds remain incompletely understood. In this study, we developed an ayahuasca-inspired formulation containing DMT and harmine, aiming to systematically evaluate their pharmacokinetic and pharmacodynamic drug-drug interactions (DDI) across a range of dosage levels. We hypothesized that escalating harmine doses would enhance DMT bioavailability, increase its plasma half-life, and reduce the variability in DMT plasma concentrations between individuals. Additionally, we expected that harmine would attenuate the plasma levels of the main DMT metabolite, indole-3-acetic acid (3-IAA), while increasing levels of the secondary metabolite DMT-N-oxide (DMT-NO). This single-blind, randomized, two-arm, factorial, dose-finding study included 16 healthy participants (9 males, 7 females), each receiving six dose combinations (0-120 mg DMT, 0-180 mg harmine) administered via a microcarrier-based transmucosal delivery system. We then evaluated the pharmacokinetics of DMT and harmine and their main metabolites, subjective effects, autonomic responses, and the safety profile of the combined preparation. All DMT-harmine combinations reliably induced dose-dependent subjective effects lasting 4-5 h, with peak DMT and harmine levels (Cmax) reaching 33 ng/mL and 49 ng/mL, respectively. Tmax, the time to maximum concentrations, increased with dose escalation for both compounds. The interactions between DMT and harmine were not unidirectional, i.e., harmine reduced the metabolism of DMT, while DMT altered harmine pharmacokinetics. Our novel formulation demonstrated a favorable safety profile, supporting its potential for further testing in patients with various affective disorders.

Quantitative evaluation of multiple treatment regimens for treatment-resistant depression

OBJECTIVE

This study aims to quantitatively evaluate the efficacy and safety of various treatment regimens for treatment-resistant depression (TRD) across oral, intravenous, and intranasal routes to inform clinical guidelines.

METHODS

A systematic review identified randomized controlled trials on TRD, with efficacy measured by changes in the Montgomery-Åsberg Depression Rating Scale (MADRS). We developed pharmacodynamic and covariate models for different administration routes, using Monte Carlo simulations to estimate efficacy distribution. Dropout and adverse event-related dropout rates were analyzed via single-arm meta-analysis.

RESULTS

Involving 22 studies with 56 treatment arms and 3059 patients, our findings suggest combination therapies outperform monotherapy, achieving an additional 6.5% reduction in MADRS scores over 12 weeks. The most effective combinations were olanzapine with fluoxetine and quetiapine with selective serotonin reuptake inhibitors/ selective serotonin and norepinephrine reuptake inhibitors. Injectable treatments, particularly ayahuasca, produced rapid effects, with a 77% reduction in MADRS scores at 15 days. Intranasal treatments reached efficacy sooner than oral ones, with 28-day efficacy similar to the 12-week efficacy of the olanzapine-fluoxetine combination. Dropout rates due to adverse events were similar across methods (4.5%-5.2%), but total dropouts were highest for oral (17.9%) and lowest for intranasal routes (10.6%). Additionally, there was considerable variation in the incidence of headache, dizziness, and nausea across different administration routes.

CONCLUSIONS

The quantitative evaluation of 22 TRD treatments illuminates key pharmacodynamic parameters, bolstering the development of clinical guidelines and aiding the design of clinical trials and medical decision-making.

Benefits and Challenges of Ultra-Fast, Short-Acting Psychedelics in the Treatment of Depression

Unlike classical antidepressants, psychedelics such as psilocybin have been shown to induce a rapid antidepressant response. In the wake of this development, interest has emerged in ultra-fast, short-acting psychedelics such as 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and N,N-dimethyltryptamine (DMT) with the expectation that these can produce rapid antidepressant effects following an intense but brief psychedelic intervention. The current paper reviews the clinical pharmacology of 5-MeO-DMT and DMT and their potential benefits and challenges in the treatment of depression. Both compounds display affinities for a variety of monoamine receptors and transporters, but mostly so for serotonergic (5HT) receptors, including 5HT1A and 5HT2A. Early clinical trials in small samples have shown that short interventions (15-30 min) with 5-MeO-DMT and DMT are safe and well tolerated and can induce marked improvement in symptoms of depression within 24 hours that sustain for at least 1 week. Data on long-term efficacy are currently scarce but do suggest a prolongation of the treatment response. Potential benefits of these treatments include flexible, single day dosing regimens, achievement of treatment efficacy independent from integrative therapy, and ease of clinical implementation. Future challenges include establishing the duration of the antidepressant effect and strategies on how to sustain the antidepressant response, optimization of treatment delivery parameters, and a mechanistic understanding of the clinical response. Acceptance of ultra-fast, short-acting psychedelics will depend on future randomized, placebo-controlled trials with a focus on replication, duration and maintenance of antidepressant efficacy in large patient samples.

Effects of psychedelics on neurogenesis and broader neuroplasticity: a systematic review

In the mammalian brain, new neurons continue to be generated throughout life in a process known as adult neurogenesis. The role of adult-generated neurons has been broadly studied across laboratories, and mounting evidence suggests a strong link to the HPA axis and concomitant dysregulations in patients diagnosed with mood disorders. Psychedelic compounds, such as phenethylamines, tryptamines, cannabinoids, and a variety of ever-growing chemical categories, have emerged as therapeutic options for neuropsychiatric disorders, while numerous reports link their effects to increased adult neurogenesis. In this systematic review, we examine studies assessing neurogenesis or other neurogenesis-associated brain plasticity after psychedelic interventions and aim to provide a comprehensive picture of how this vast category of compounds regulates the generation of new neurons. We conducted a literature search on PubMed and Science Direct databases, considering all articles published until January 31, 2023, and selected articles containing both the words "neurogenesis" and "psychedelics". We analyzed experimental studies using either in vivo or in vitro models, employing classical or atypical psychedelics at all ontogenetic windows, as well as human studies referring to neurogenesis-associated plasticity. Our findings were divided into five main categories of psychedelics: CB1 agonists, NMDA antagonists, harmala alkaloids, tryptamines, and entactogens. We described the outcomes of neurogenesis assessments and investigated related results on the effects of psychedelics on brain plasticity and behavior within our sample. In summary, this review presents an extensive study into how different psychedelics may affect the birth of new neurons and other brain-related processes. Such knowledge may be valuable for future research on novel therapeutic strategies for neuropsychiatric disorders.

New frontiers in the biosynthesis of psychoactive specialized metabolites

The recent relaxation of psychedelic drug regulations has prompted extensive clinical investigation into their potential use to treat diverse mental health conditions including anxiety, depression, post-traumatic stress, and substance-abuse disorders. Most clinical trials have relied on a small number of known molecules found in nature, such as psilocybin, or long-known synthetic analogs of natural metabolites, including lysergic acid diethylamide (LSD). Elucidation of biosynthetic pathways leading to several psychedelic compounds has established an opportunity to use synthetic biology as a complement to synthetic chemistry for the preparation of novel derivatives with potentially superior pharmacological properties compared with known drugs. Herein we review the metabolic biochemistry of pathways from plants, fungi and animals that yield the medicinally important hallucinogenic specialized metabolites ibogaine, mescaline, psilocybin, lysergic acid, and N,N-dimethyltryptamine (DMT). We also summarize the reconstitution of these pathways in microorganisms and comment on the integration of native and non-native enzymes to prepare novel derivatives.

Psychedelic research, assisted therapy and the role of the anaesthetist: A review and insights for experimental and clinical practices

Recent years have witnessed an unprecedented increase in the search for the use of psychedelics in improving physical and mental health. Anaesthesia has evolved since very early times, born from the need to eliminate pain and reduce suffering and there are reports of the use of anaesthetics to achieve mystical states since the nineteenth century. Nowadays, the renaissance of psychedelics in anaesthesia has been inspired by their potential in the treatment of chronic pain syndromes, palliative care and in the emergency department and pre-hospital care with the administration of psychedelics in cases of ischaemia, given their potential in neuroprotection. Although there are already some published protocols for the administration of psychedelics in patients with mental illness, little has been addressed concerning non-mental medical applications. In this sense, in patients with multiple comorbidities, functional limitations and polymedicated, the anaesthetist may play a fundamental role, not only in clinical practice, but also in translational research. This article focuses on the description of psychedelics, with a particular focus on dimethyltryptamine (DMT) and ayahuasca pharmacology, effects, safety and toxicity. A detailed description of the role of the anaesthetist in clinical and experimental research is provided, from participant's screening to preparation and dosing session, expected adverse effects and how to manage them, based on the protocol and standard procedures of a current study with neuroimaging during the psychedelic experience. Specific considerations regarding the management of psychedelic toxicity are also provided as well as future directions for safe psychedelic use in clinical practice.

Effects of classical psychedelics on implicit and explicit emotional empathy and cognitive empathy: a meta-analysis of MET task

This meta-analysis investigates the effect of classic psychedelic drugs on empathy and focuses on cognitive and emotional empathy measured using the Multifaceted Empathy Test (MET). Empathy entails the ability to understand and share the feelings of another and is a significant component of social interaction. Several studies have examined the effects of psychedelic drugs such as LSD, psilocybin and ayahuasca on empathy, yet their overall effect has not been studied so far. In this meta-analysis, we reviewed data from studies up to November 2023 with the aim of examining the effects of various psychedelic drugs on empathic abilities broadly. Our findings suggest that classical psychedelics significantly enhance explicit and implicit emotional empathy without affecting measures of cognitive empathy. The results emphasize the need to continue testing the therapeutic potential of classic psychedelic drugs.

Neurobiological research on N,N-dimethyltryptamine (DMT) and its potentiation by monoamine oxidase (MAO) inhibition: from ayahuasca to synthetic combinations of DMT and MAO inhibitors

The potent hallucinogen N,N-dimethyltryptamine (DMT) has garnered significant interest in recent years due to its profound effects on consciousness and its therapeutic psychopotential. DMT is an integral (but not exclusive) psychoactive alkaloid in the Amazonian plant-based brew ayahuasca, in which admixture of several β-carboline monoamine oxidase A (MAO-A) inhibitors potentiate the activity of oral DMT, while possibly contributing in other respects to the complex psychopharmacology of ayahuasca. Irrespective of the route of administration, DMT alters perception, mood, and cognition, presumably through agonism at serotonin (5-HT) 1A/2A/2C receptors in brain, with additional actions at other receptor types possibly contributing to its overall psychoactive effects. Due to rapid first pass metabolism, DMT is nearly inactive orally, but co-administration with β-carbolines or synthetic MAO-A inhibitors (MAOIs) greatly increase its bioavailability and duration of action. The synergistic effects of DMT and MAOIs in ayahuasca or synthetic formulations may promote neuroplasticity, which presumably underlies their promising therapeutic efficacy in clinical trials for neuropsychiatric disorders, including depression, addiction, and post-traumatic stress disorder. Advances in neuroimaging techniques are elucidating the neural correlates of DMT-induced altered states of consciousness, revealing alterations in brain activity, functional connectivity, and network dynamics. In this comprehensive narrative review, we present a synthesis of current knowledge on the pharmacology and neuroscience of DMT, β-carbolines, and ayahuasca, which should inform future research aiming to harness their full therapeutic potential.

Ayahuasca for the treatment of alcohol use disorder

For decades, psychedelics have been investigated for the treatment of psychiatric disorders. Specifically, evidence suggests that psychedelics may have therapeutic potential for the treatment of alcohol use disorder. Several studies with classic psychedelics, including LSD and psilocybin, show promising results, with psychedelics decreasing alcohol drinking and promoting abstinence in individuals with alcohol use disorder. In the last two decades, ayahuasca has emerged as another psychedelic with therapeutic potential for alcohol use disorder. Although its use by indigenous people from South America has been reported for thousands of years, ayahuasca, an Amazonian brewed beverage used in rituals, has gained attention in recent decades due to its reported effects in the central nervous system. Ayahuasca is a hallucinogenic beverage produced from the decoction of Banisteriopsis caapi and Psychotria viridis, plants that contain β-carbolines and N,N-dimethyltryptamine (DMT), respectively. The majority of clinical studies investigating ayahuasca for the treatment of alcohol use disorder are retrospective, and all show a significant decrease in alcohol use among ayahuasca users. Corroborating the clinical evidence, pre-clinical studies also have demonstrated that ayahuasca can block several of the abuse-related effects of alcohol. This chapter reviews the accumulating evidence from clinical and pre-clinical studies suggesting that ayahuasca may be a promising new pharmacotherapy for the treatment of alcohol use disorders, and discusses the potential mechanisms involved in these and other effects of ayahuasca.

Ayahuasca-enhanced extinction of fear behaviour: Role of infralimbic cortex 5-HT2A and 5-HT1A receptors

BACKGROUND AND PURPOSE

Ayahuasca (AYA) is a botanical psychedelic with promising results in observational and small clinical trials for depression, trauma and drug use disorders. Its psychoactive effects primarily stem from N,N-dimethyltryptamine (DMT). However, there is a lack of research on how and where AYA acts in the brain. This study addressed these questions by examining the extinction of aversive memories in AYA-treated rats.

EXPERIMENTAL APPROACH

We focused on the 5-HT1A and 5-HT2A receptors, as DMT exhibits a high affinity for both of them, along with the infralimbic cortex in which activity and plasticity play crucial roles in regulating the mnemonic process under analysis.

KEY RESULTS

A single oral treatment with AYA containing 0.3 mg·kg-1 of DMT increased the within-session extinction of contextual freezing behaviour without affecting its recall. This protocol, when repeated twice on consecutive days, enhanced extinction recall. These effects were consistent for both 1- and 21-day-old memories in males and females. AYA effects on fear extinction were independent of changes in anxiety and general exploratory activity: AYA- and vehicle-treated animals showed no differences when tested in the elevated plus-maze. The 5-HT2A receptor antagonist MDL-11,939 and the 5-HT1A receptor antagonist WAY-100635 infused into the infralimbic cortex respectively blocked within- and between-session fear extinction effects resulting from repeated oral administration of AYA.

CONCLUSION AND IMPLICATIONS

Our findings highlight complementary mechanisms by which AYA facilitates the behavioural suppression of aversive memories in the rat infralimbic cortex. These results suggest potential beneficial effects of AYA or DMT in stress-related disorders.

Ayahuasca and its major component harmine promote antinociceptive effects in mouse models of acute and chronic pain

ETHNOPHARMACOLOGICAL RELEVANCE

Ayahuasca (AYA) is a psychedelic brew used in religious ceremonies. It is broadly used as a sacred medicine for treating several ailments, including pain of various origins.

AIM OF THE STUDY

To investigate the antinociceptive effects of AYA and its mechanisms in preclinical models of acute and chronic pain in mice, in particular during experimental neuropathy.

MATERIALS AND METHODS

The antinociceptive effects of AYA administered orally were assessed in the following models of pain: formalin test, Complete Freund's Adjuvant (CFA)-induced inflammation, tail flick test, and partial sciatic nerve ligation model of neuropathic pain. Antagonism assays and Fos immunohistochemistry in the brain were performed. AYA-induced toxicity was investigated. AYA was chemically characterized. The antinociceptive effect of harmine, the major component present in AYA, was investigated.

RESULTS

AYA (24-3000 μL/kg) dose-dependently reduced formalin-induced pain-like behaviors and CFA-induced mechanical allodynia but did not affect CFA-induced paw edema or tail flick latency. During experimental neuropathy, single treatments with AYA (24-3000 μL/kg) reduced mechanical allodynia; daily treatments once or twice a day for 14 days promoted consistent and sustained antinociception. The antinociceptive effect of AYA (600 μL/kg) was reverted by bicuculline (1 mg/kg) and methysergide (5 mg/kg), but not by naloxone (5 mg/kg), phaclofen (2 mg/kg), and rimonabant (10 mg/kg), suggesting the roles of GABAA and serotonergic receptors. AYA increased Fos expression in the ventrolateral periaqueductal gray and nucleus raphe magnus after 1 h, but not after 6 h or 14 days of daily treatments. AYA (600 μL/kg) twice a day for 14 days did not alter mice's motor function, spontaneous locomotion, body weight, food and water intake, hematological, biochemical, and histopathological parameters. Harmine (3.5 mg/kg) promoted consistent antinociception during experimental neuropathy.

CONCLUSIONS

AYA promotes consistent antinociceptive effects in different mouse models of pain without inducing detectable toxic effects. Harmine is at least partially accountable for the antinociceptive properties of AYA.

Ayahuasca ceremony leaders' perspectives on special considerations for eating disorders

Eating disorders (EDs) are difficult conditions to resolve, necessitating novel treatments. Ayahuasca, a psychedelic plant medicine originating in Indigenous Amazonian communities, is being investigated. Aspects of ceremonial ayahuasca use (purging, dietary restrictions) appear similar to ED behaviors, raising questions about ayahuasca's suitability as an intervention for individuals with EDs. This study explored the perspectives of ayahuasca ceremony leaders on these and other considerations for ceremonial ayahuasca drinking among individuals with EDs. A qualitative content analysis of interviews was undertaken with 15 ayahuasca ceremony leaders, the majority of whom were from the West/Global North. Screening for EDs, purging and dietary restrictions, potential risks and dangers, and complementarity with conventional ED treatment emerged as categories. The findings offer ideas, including careful screening and extra support, to promote safe and beneficial ceremony experiences for ceremony participants with EDs. More research is needed to clarify the impacts of ceremony-related purging and preparatory diets. To evolve conventional models of treatment, the ED field could consider Indigenous approaches to mental health whereby ayahuasca ceremony leaders and ED researchers and clinicians collaborate in a decolonizing, bidirectional bridging process between Western and Indigenous paradigms of healing.

Established sensitization of ethanol-induced locomotor activity is not reversed by psilocybin or the 5-HT2A receptor agonist TCB-2 in male DBA/2J mice

RATIONALE

Psychedelic drugs, which share in common 5-HT2A receptor agonist activity, have shown promise in treating alcohol-use disorders (AUDs). Repeated exposure to ethanol (EtOH) induces molecular and behavioural changes reflective of neuroadaptations that may contribute to addiction. Psychedelic drugs can induce neuroplasticity also, raising the possibility that their potential clinical effects in AUD may involve an action to reverse or offset effects of long-term changes induced by EtOH. This possibility was examined by investigating whether psilocybin, or the 5-HT2A receptor agonist TCB-2, counteracted established sensitization of EtOH-induced locomotor activity.

METHODS

Male DBA/2J mice received repeated injections of 2.2 g/kg EtOH to induce a sensitized locomotor activity response. In two experiments separate groups of mice were then injected with psilocybin (0, 0.3 and 1 kg/kg) or TCB-2 (0, 1 and 3 mg/kg) on 5 consecutive days. Next, mice were challenged with 1.8 g/kg EtOH and locomotor activity measured for 15 min.

RESULTS

Relative to naïve controls, previously sensitized mice showed enhanced locomotor activity to the challenge dose. Despite reducing locomotor activity in their own right psilocybin and TCB-2 did not alter the strength of this sensitized response.

CONCLUSION

Psilocybin and TCB-2 at behaviourally effective doses did not reverse sensitization of EtOH-induced activity. This suggests that mechanisms involved in mediating short-term reductions in EtOH intake by psilocybin or TCB-2 may not involve a capacity of these drugs to offset enduring changes in behaviour and any underlying neural adaptations induced by repeated intermittent exposure to EtOH.

Potential therapeutic effects of an ayahuasca-inspired N,N-DMT and harmine formulation: a controlled trial in healthy subjects

Background

There is growing scientific evidence for the therapeutic benefits of the Amazonian plant-based psychedelic "ayahuasca" for neuropsychiatric disorders such as depression and anxiety. However, there are certain challenges when incorporating botanical ayahuasca into biomedical research and clinical therapy environments. Formulations inspired by ayahuasca, which contain specific and standardized active components, are a potential remedy.

Methods

We investigated subjective acute and persisting effects of a novel formulation containing the reversible monoamine oxidase inhibitor harmine (orodispersible tablet containing 100 mg MAO-I) and N,N-dimethyltryptamine (incremental intranasal dosing of up to 100 mg DMT), compared with two other conditions, namely harmine alone and placebo, in a crossover RCT in 31 healthy male subjects.

Results

DMT + harmine, but not harmine alone, induced a psychedelic experience assessed with the 5D-ASC rating scale [global score: F(2,60) = 80.21, p < 0.001] and acute experience sampling items over time, characterized by psychological insights [PIQ, F(2,58.5) = 28.514, p < 0.001], emotional breakthroughs [EBI, F(2,60) = 26.509, p < 0.001], and low scores on the challenging experience questionnaire [CEQ, F(2,60) = 12.84, p < 0.001]. Participants attributed personal and spiritual significance to the experience (GSR) with mainly positive persisting effects (PEQ) at 1- and 4-months follow-up. Acute drug effects correlated positively with persisting effects. We found no changes in trait measures of personality, psychological flexibility, or general well-being, and no increases in psychopathology (SCL-90-R) were reported.

Discussion and Conclusion

Our results suggest that the experience induced by the standardized DMT + harmine formulation induces a phenomenologically rich psychedelic experience, demonstrates good psychological safety and tolerability, is well tolerated, and induces beneficial psychological processes that could possibly support psychotherapy. Further studies are required to investigate the psychotherapeutic potential in patients.

Efficacy, Safety, and Tolerability of Psychedelics in Treatment-Resistant Depression (TRD)

Major depressive disorder (MDD) is a highly prevalent psychiatric disorder, associated with substantial burden and large economical costs. Notwithstanding various conventional antidepressant treatment options, a large portion of depressed people (ca. 30%) fails to respond to first-line treatment, resulting in treatment-resistant depression (TRD). Although non-response to multiple antidepressant interventions is a common outcome, a consensus definition of TRD is not yet available. In practice, TRD is applied when two or more successive treatments with different antidepressants are not working. The last decade's intense research into new medicines for TRD has led to two developments, using typical or serotonergic (psilocybin, ayahuasca) and atypical (glutamatergic) psychedelics (ketamine, esketamine). Both approaches, although via different entrance mechanism, exhibit a fast onset but also long-lasting antidepressant effect far beyond the biological presence of the drug in the body, strongly indicating that downstream mechanisms activated by signaling cascades in the brain are involved. The present chapter describes the clinical development of psilocybin and esketamine for TRD and discusses the problems involved in the use of a proper placebo because of the psychotomimetic (psilocybin) or dissociative (ketamine) effects that interfere with performing "blind" studies. Nevertheless, intranasal esketamine was developed and approved for TRD, whereas psilocybin has shown positive results. Adverse effects and tolerability of both drugs in the dose ranges used are generally acceptable. The emergence of anti-TRD medicines for treatment of a very severe disease is a breakthrough in psychiatry.

Psychological and physiological effects of extended DMT

N,N-Dimethyltryptamine (DMT) is a serotonergic psychedelic that induces a rapid and transient altered state of consciousness when inhaled or injected via bolus administration. Its marked and novel subjective effects make DMT a powerful tool for the neuroscientific study of consciousness and preliminary results show its potential role in treating mental health conditions. In a within-subjects, placebo-controlled study, we investigated a novel method of DMT administration involving a bolus injection paired with a constant-rate infusion, with the goal of extending the DMT experience. Pharmacokinetic parameters of DMT estimated from plasma data of a previous study of bolus intravenous DMT were used to derive dose regimens necessary to keep subjects in steady levels of immersion into the DMT experience over an extended period of 30 min, and four dose regimens consisting of a bolus loading dose and a slow-rate infusion were tested in eleven healthy volunteers (seven male, four female, mean age ± SD = 37.09 ± 8.93 years). The present method is effective for extending the DMT experience in a stable and tolerable fashion. While subjective effects were maintained over the period of active infusion, anxiety ratings remained low and heart rate habituated within 15 min, indicating psychological and physiological safety of extended DMT. Plasma DMT concentrations increased consistently starting 10 min into DMT administration, whereas psychological effects plateaued into the desired steady state, suggesting the development of acute psychological tolerance to DMT. Taken together, these findings demonstrate the safety and effectiveness of continuous IV DMT administration, laying the groundwork for the further development of this method of administration for basic and clinical research.

Ayahuasca: A review of historical, pharmacological, and therapeutic aspects

Ayahuasca is a psychedelic plant brew originating from the Amazon rainforest. It is formed from two basic components, the Banisteriopsis caapi vine and a plant containing the potent psychedelic dimethyltryptamine (DMT), usually Psychotria viridis. Here we review the history of ayahuasca and describe recent work on its pharmacology, phenomenological responses, and clinical applications. There has been a significant increase in interest in ayahuasca since the turn of the millennium. Anecdotal evidence varies significantly, ranging from evangelical accounts to horror stories involving physical and psychological harm. The effects of the brew on personality and mental health outcomes are discussed in this review. Furthermore, phenomenological analyses of the ayahuasca experience are explored. Ayahuasca is a promising psychedelic agent that warrants greater empirical attention regarding its basic neurochemical mechanisms of action and potential therapeutic application.

Overcoming the clinical challenges of traditional ayahuasca: a first-in-human trial exploring novel routes of administration of N,N-Dimethyltryptamine and harmine

Recently, the Amazonian plant medicine "ayahuasca"-containing the psychedelic compound N,N-dimethyltryptamine (DMT) and numerous β-carboline alkaloids, such as harmine-has been suggested to exhibit beneficial effects in patients with affective and other mental health disorders. Although ayahuasca ingestion is considered safe, its pharmacokinetics/pharmacodynamics and tolerability profile pose some challenges and may limit the clinical applicability in vulnerable patient populations. While overdosing and the admixture of intolerable plant constituents may explain some of the common adverse reactions, the peroral route of administration may represent another relevant source of gastro-intestinal intolerabilities and unpredictable pharmacokinetics across users. To overcome these challenges, the present work aimed at creating ayahuasca-analogue formulations with improved pharmacokinetics and tolerability profiles. To this end, we developed peroral formulas and compared them with parenteral formulas specifically designed to circumvent the gastro-intestinal tract. In more detail, peroral administration of a capsule (containing purified DMT and harmine) was tested against a combined administration of an oromucosal harmine tablet and an intranasal DMT spray at two dose levels in an open-label within-subject study in 10 healthy male subjects. Pharmacokinetic and pharmacodynamic profiles were assessed by means of continuous blood sampling, vital sign monitoring, and psychometric assessments. Common side effects induced by traditional herbal ayahuasca such as nausea, vomiting, and diarrhea were significantly attenuated by our DMT/harmine formulations. While all preparations were well tolerated, the combined buccal/intranasal administration of harmine and DMT yielded substantially improved pharmacokinetic profiles, indicated by significantly reduced variations in systemic exposure. In conclusion, the combined buccal/intranasal administration of harmine and DMT is an innovative approach that may pave the way towards a safe, rapid-acting, and patient-oriented administration of DMT/harmine for the treatment of affective disorders. Clinical Trial Registration: clinicaltrials.gov, identifier NCT04716335.

A Systematic Review on the Therapeutic Effects of Ayahuasca

Traditional therapies, resorting to the use of plants, have acquired a great demand over the years, both for economic reasons and the preference for natural treatments. Some studies suggest that ayahuasca may have beneficial properties in treating some physical and psychological imbalances. Thus, we carried out a systematic review of studies published up to December 2022, where these themes were addressed. The search was carried out in the PubMed database, and only studies written in English and published in peer-reviewed journals were included. Thus, 228 publications were identified, of which 66 were included in the present study. The reviewed studies suggest that ayahuasca may have beneficial effects on various physical and psychological conditions, namely in the treatment of depression, anxiety and various diseases of the neurobiological system, as well as anti-inflammatory and antimicrobial properties, demonstrating its therapeutic potential. The number of studies that address this issue has also been growing, demonstrating interest in the search for alternative treatments. However, to the best of our knowledge, this is the first systematic review where all the findings of therapeutic effects associated with the consumption of ayahuasca are reviewed.

Awake or Sleeping? Maybe Both… A Review of Sleep-Related Dissociative States

Recent studies have begun to understand sleep not only as a whole-brain process but also as a complex local phenomenon controlled by specific neurotransmitters that act in different neural networks, which is called "local sleep". Moreover, the basic states of human consciousness-wakefulness, sleep onset (N1), light sleep (N2), deep sleep (N3), and rapid eye movement (REM) sleep-can concurrently appear, which may result in different sleep-related dissociative states. In this article, we classify these sleep-related dissociative states into physiological, pathological, and altered states of consciousness. Physiological states are daydreaming, lucid dreaming, and false awakenings. Pathological states include sleep paralysis, sleepwalking, and REM sleep behavior disorder. Altered states are hypnosis, anesthesia, and psychedelics. We review the neurophysiology and phenomenology of these sleep-related dissociative states of consciousness and update them with recent studies. We conclude that these sleep-related dissociative states have a significant basic and clinical impact since their study contributes to the understanding of consciousness and the proper treatment of neuropsychiatric diseases.

Acute effects of intravenous DMT in a randomized placebo-controlled study in healthy participants

N,N-dimethyltryptamine (DMT) is distinct among classic serotonergic psychedelics because of its short-lasting effects when administered intravenously. Despite growing interest in the experimental and therapeutic use of intravenous DMT, data are lacking on its clinical pharmacology. We conducted a double-blind, randomized, placebo-controlled crossover trial in 27 healthy participants to test different intravenous DMT administration regimens: placebo, low infusion (0.6 mg/min), high infusion (1 mg/min), low bolus + low infusion (15 mg + 0.6 mg/min), and high bolus + high infusion (25 mg + 1 mg/min). Study sessions lasted for 5 h and were separated by at least 1 week. Participant's lifetime use of psychedelics was ≤20 times. Outcome measures included subjective, autonomic, and adverse effects, pharmacokinetics of DMT, and plasma levels of brain-derived neurotropic factor (BDNF) and oxytocin. Low (15 mg) and high (25 mg) DMT bolus doses rapidly induced very intense psychedelic effects that peaked within 2 min. DMT infusions (0.6 or 1 mg/min) without a bolus induced slowly increasing and dose-dependent psychedelic effects that reached plateaus after 30 min. Both bolus doses produced more negative subjective effects and anxiety than infusions. After stopping the infusion, all drug effects rapidly decreased and completely subsided within 15 min, consistent with a short early plasma elimination half-life (t_1/2α) of 5.0-5.8 min, followed by longer late elimination (t_1/2β = 14-16 min) after 15-20 min. Subjective effects of DMT were stable from 30 to 90 min, despite further increasing plasma concentrations, thus indicating acute tolerance to continuous DMT administration. Intravenous DMT, particularly when administered as an infusion, is a promising tool for the controlled induction of a psychedelic state that can be tailored to the specific needs of patients and therapeutic sessions.Trial registration: ClinicalTrials.gov identifier: NCT04353024.

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.

LSD, madness and healing: Mystical experiences as possible link between psychosis model and therapy model

BACKGROUND

For a century, psychedelics have been investigated as models of psychosis for demonstrating phenomenological similarities with psychotic experiences and as therapeutic models for treating depression, anxiety, and substance use disorders. This study sought to explore this paradoxical relationship connecting key parameters of the psychotic experience, psychotherapy, and psychedelic experience.

METHODS

In a randomized, double-blind, placebo-controlled, crossover design, 24 healthy volunteers received 50 μg d-lysergic acid diethylamide (LSD) or inactive placebo. Psychotic experience was assessed by aberrant salience (Aberrant Salience Inventory, ASI), therapeutic potential by suggestibility (Creative Imagination Scale, CIS) and mindfulness (Five Facet Mindfulness Questionnaire, FFMQ; Mindful Attention Awareness Scale, MAAS; Experiences Questionnaire, EQ), and psychedelic experience by four questionnaires (Altered State of Consciousness Questionnaire, ASC; Mystical Experiences Questionnaire, MEQ; Challenging Experiences Questionnaire, CEQ; Ego-Dissolution Inventory, EDI). Relationships between LSD-induced effects were examined.

RESULTS

LSD induced psychedelic experiences, including alteration of consciousness, mystical experiences, ego-dissolution, and mildly challenging experiences, increased aberrant salience and suggestibility, but not mindfulness. LSD-induced aberrant salience correlated highly with complex imagery, mystical experiences, and ego-dissolution. LSD-induced suggestibility correlated with no other effects. Individual mindfulness changes correlated with aspects of aberrant salience and psychedelic experience.

CONCLUSIONS

The LSD state resembles a psychotic experience and offers a tool for healing. The link between psychosis model and therapeutic model seems to lie in mystical experiences. The results point to the importance of meaning attribution for the LSD psychosis model and indicate that psychedelic-assisted therapy might benefit from therapeutic suggestions fostering mystical experiences.

Psychotherapeutic and neurobiological processes associated with ayahuasca: A proposed model and implications for therapeutic use

Ayahuasca is a psychoactive Amazonian plant brew. It is usually made from the Banisteriopsis caapi vine (Spruce ex Griseb. Morton, Malpighiaceae), which contains three primary harmala alkaloids, along with the leaves of Psychotria viridis (Ruiz et Pavon, Rubiaceae) in which the potent psychedelic dimethyltryptamine (DMT) is found. DMT-harmaloid concoctions have gained popularity in recent years, due to growing anecdotal and scientific reports of therapeutic benefits associated with their consumption. Ayahuasca is now ingested in a variety of different settings across the globe, from traditional ethnobotanical to so called "neo-shamanic" ceremonies. Furthermore, related preparations involving alternative sources of DMT and harmala alkaloids are becoming increasingly common as knowledge of ayahuasca continues to spread internationally. This article reviews the existing literature and draws on original qualitative data from a large cross-sectional study of ayahuasca drinkers, to propose a model of psychotherapeutic processes associated with the consumption of ayahuasca. We assert that it is these processes, facilitated by a range of neurobiological effects, that lead to beneficial mental health and wellbeing outcomes. Our proposed model identifies five key psychotherapeutic processes or effects inherent to the ayahuasca experience; somatic effects; introspection and emotional processing; increased Self-connection; increased spiritual connection, and finally the gaining of insights and new perspectives. We note some important differences in these processes compared with other classic psychedelics as well as the implications of the model for the therapeutic use of ayahuasca. Improved understanding of the psychotherapeutic processes involved with the ayahuasca experience will better equip practitioners to work with this potentially transformative concoction and enable the optimization of therapeutic treatment models for potential clinical use.

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.

Exploration of essential oil from Psychotria poeppigiana as an anti-hyperalgesic and anti-acetylcholinesterase agent: Chemical composition, biological activity and molecular docking

ETHNOPHARMACOLOGICAL RELEVANCE

Leaves from Psychotria poeppigiana Müll. Arg. (accepted as Palicourea tomentosa (Aubl.) Borhidi), Rubiaceae, has traditionally been used in medicine for treatments of inflammation and pain; Synonymously, Cephaelis elata for the treatment of dementia; However, few scientific studies have been evidence demonstrating this activity.

AIM OF THE STUDY

The aim of this study was to investigate the chemical composition of P. poeppigiana essential oil obtained from leaves (EOPP) and its antioxidant, anti-inflammatory and acetylcholinesterase (AChE) activities. Molecular docking simulations were carried out with the main constituents.

MATERIALS AND METHODS

EOPP (hydrodistillation) was analysed by gas chromatography-mass spectrometry (GC-MS). The fractionation of EOPP afforded germacrene D and bicyclogermacrene. The antioxidant activity of EOPP was determined by MDA assay. The inflammatory parameters were evaluated using CFA model (with paw edema, mechanical, thermal hyperalgesia, MPO and NAG) in EOPP (30, 100 and 300 mg/kg), germacrene D and bicyclogermacrene (30 mg/kg). The AChE inhibition was evaluated in rat brain structures and molecular docking simulations were carried out using Autodock v.4.3.2.

RESULTS

GC-MS analysis identified 19 compounds, and the major compounds were germacrene D (29.38%) and bicyclogermacrene (25.21%). EOPP exhibited high antioxidant capacity (IC₅₀ = 12.78 ± 1.36 μg/mL). All the tested doses of EOPP and both major constituents significantly inhibited cold and mechanical hyperalgesia and significantly blocked the increase in MPO activity 24 h after the CFA injection. There was significant AChE inhibition by EOPP and germacrene D in the cerebral cortex and hippocampus (>50%). Enzyme-ligand molecular modelling showed that the major constituents of EOPP interacted differently with AChE.

CONCLUSIONS

The chemical compounds of the essential oil from the leaves of P. poeppigiana is based mainly on terpenes, the sesquiterpenes germacrene D (29.38%) and bicyclogermacrene (25.21%) being the major compounds. EOPP presented antioxidant, anti-inflammatory and anti-acetylcholinesterase (AChE) activities. Besides, enzyme-ligand molecular modelling showed the EOPP may act as an anti-hyperalgesic and AChE inhibitory agent. Taken together, these results might be in accordance with if folk use for pain- and inflammation-related symptoms.

Antidepressant and anxiolytic-like effects of ayahuasca in rats subjected to LPS-induced neuroinflammation

The objective of this study was to evaluate the behavioral response of ayahuasca in rats submitted to neuroinflammation through the intraperitoneal application of lipopolysaccharide (0.63 mg/kg/mL). Eighty animals, male, about 90 days old, were divided into control and LPS groups and later into prevention and treatment subgroups. The prevention subgroup was administered ayahuasca or saline solution, via gavage, at a dose of 4 mL/kg one hour before applying LPS or saline, while the treatment subgroup received the same dose of the respective substances 24 h after intraperitoneal applications. Behavioral parameters were evaluated using open field (anxiety-like) and forced swimming (depressive-like) tests. A decrease in LPS/AYA rats in the prevention and treatment subgroups regarding anxiety-like behavior was observed. As for the depressive-like behavior, there was a decrease in the group induced to the disease model, both in the prevention subgroup (when compared to the SAL/SAL, SAL/AYA, and LPS/AYA with LPS/SAL groups) and in the treatment (when comparing SAL/SAL and LPS/AYA with LPS/SAL). This study concludes the anxiolytic and antidepressant potential of ayahuasca in an animal model of neuroinflammation, possibly due to the antineuroinflammatory effects already reported of the compound.

β-carboline-independent antidepressant-like effect of the standardized extract of the barks of Mimosa tenuiflora (Willd) Poir. occurs via 5-HT2A/2C receptors in mice

BACKGROUND

Depression is a psychiatric disorder with limited therapy options. Psychedelics are new antidepressant candidates, being the ayahuasca one of the most promising ones. A synergistic combination of N,N-dimethyltryptamine (DMT) and β-carbolines allows ayahuasca antidepressant properties. Another psychedelic and DMT-containing beverage is the jurema wine used religiously by indigenous people from Northeastern Brazil.

AIMS

To evaluate the antidepressant-like effect of standardized extract of Mimosa tenuiflora (SEMT), associated or not with harmine (β-carboline), in behavioral models of depression.

METHODS

The SEMT was submitted to (+) ESI-IT-LC/MS analysis for DMT quantification. To assess the antidepressant-like effect of SEMT, the open field (OFT), tail suspension (TST), and forced swim (FST) tests were performed. To verify the participation of serotonergic systems, the 5-hydroxytryptophan (5-HTP)-induced head twitch test was performed.

RESULTS

The content of DMT found in SEMT was 24.74 ± 0.8 mg/g. Yuremamine was also identified. SEMT presented an antidepressant-like effect in mice submitted to the TST and FST, independent from harmine, with no significant alterations on the OFT. The sub-dose interaction between SEMT and ketamine also produced an anti-immobility effect in the TST, with no changes in the OFT. SEMT potentiated the head twitch behavior induced by 5-HTP and ketanserin prevented its antidepressant-like effect in the TST (p < 0.05).

CONCLUSIONS

SEMT presented a harmine-independent antidepressant-like effect in mice submitted to the TST and FST. This effect occurs possibly via activation of serotonergic systems, particularly the 5-HT_2A/2C receptors.

Ayahuasca and tobacco smoking cessation: results from an online survey in Brazil

RATIONALE

Smoking-related disease is a major problem globally. Effective smoking cessation treatments are however limited. Increasing evidence suggests that psychedelics have potential as treatments for substance use disorders and may therefore prove an option in aiding smoking cessation.

OBJECTIVES

To establish which factors predict smoking cessation in people who reported quitting or reducing smoking following ayahuasca consumption.

METHODS

A retrospective cross-sectional mixed-method study (quantitative and qualitative design) was undertaken using data from an online survey evaluating peoples' experiences before and after drinking ayahuasca. Multivariate logistic regression was performed with smoking condition (cessation or reduction/relapse) as a dependent variable and demographics, smoking, ayahuasca-related variables and the mystical experience (MEQ30) as predicting factors.

RESULTS

A total of 441 responses were grouped according to self-reported smoking status: cessation (n = 305) or reduction/relapse (n = 136) smoking. Logistic regression showed that mystical experience (OR: 1.03; 95% CI [1.00-1.05]) and frequency of ayahuasca intake (OR: 2.16[1.00-4.70]) were protective factors, while positive mood (measured by the MEQ30) during the ayahuasca experience was a risk factor (OR: 0.91[0.85-0.97]). Qualitative thematic analysis identified eight themes (e.g. acquired awareness, spiritual experience, increased motivation) related to the ayahuasca experience and the process of smoking cessation/reduction.

CONCLUSIONS

Our results suggest that ayahuasca could be used as a potential tool for smoking cessation, and that effects may be mediated by mystical experience. Given the current burden of smoking-related disease and the limited treatment options, studies are needed to investigate the efficacy of psychedelics in smoking cessation.

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.

New Insights into the Chemical Composition of Ayahuasca

Ayahuasca is a psychedelic beverage originally from the Amazon rainforest used in different shamanic settings for medicinal, spiritual, and cultural purposes. It is prepared by boiling in water an admixture of the Amazonian vine Banisteriopsis caapi, which is a source of β-carboline alkaloids, with plants containing N,N-dimethyltryptamine, usually Psychotria viridis. While previous studies have focused on the detection and quantification of the alkaloids present in the drink, less attention has been given to other nonalkaloid components or the composition of the solids suspended in the beverage, which may also affect its psychoactive properties. In this study, we used nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) to study the composition of ayahuasca samples, to determine their alkaloid qualitative and quantitative profiles, as well as other major soluble and nonsoluble components. For the first time, fructose was detected as a major component of the samples, while harmine (a β-carboline previously described as an abundant alkaloid in ayahuasca) was found to be present in the solids suspended in the beverage. In addition, N,N-dimethyltryptamine (DMT), harmine, tetrahydroharmine, harmaline, and harmol were identified as the major alkaloids present in extracts of all samples. Finally, a novel, easy, and fast method using quantitative NMR was developed and validated to simultaneously quantify the content of these alkaloids found in each ayahuasca sample.

Teacher plants - Indigenous Peruvian-Amazonian dietary practices as a method for using psychoactives

ETHNOPHARMACOLOGICAL RELEVANCE

Indigenous groups of the Amazon have developed intricate methods for the application of psychoactives, among which particularly the dieta or diet method of Peruvian-Amazonian traditional medicine stands out. It is a retreat-like intervention involving lengthy periods of social, behavioural, and alimentary restrictions, while ingesting specially prepared plant substances. The interplay of the dietary conditions and plants ingested sensitizes the dieter to receive healing, strength, guidance, and knowledge. From a clinical scientific point of view, the method has remained largely underexplored, but seems more pertinent than ever given the increasing interest in Amazonian psychoactive preparations including ayahuasca (Banisteriopsis caapi) and the burgeoning field of psychedelic-assisted therapies in general.

AIM OF THE STUDY

This study offers a descriptive account and emic interpretation of the Peruvian-Amazonian dieta. More specifically we document in detail the procedure, its context and purpose of application, effects, modes of action, adverse effects, and risks, from the perspectives of a sample of Peruvian traditional healers. The Peruvian-Amazonian dieta is a multi-purpose method for making use of medicinal plants, many of which (but not all), are psychoactive; the current work especially focuses on its therapeutic applications in conjunction with psychoactives.

METHODS

We interviewed 16 healers working in the Ucayali, San Martín, and Loreto provinces of Peru using a semi-structured interview approach. Interviews were audio-recorded and transcribed verbatim. The extensive data derived from these interviews were analysed by means of computer-assisted manifest qualitative content analysis using a theory-advancing approach. Over 500 coded text segments were categorized, resulting in 7 main theme clusters and corresponding sub-themes.

RESULTS

The interviewed healers described a complex intervention with multifaceted applications (treatment, prevention, training) and effects in various domains (body, mind, spirit, energy). The process was portrayed as transformative, with benefits attributed to the effects of the so-called teacher plants in conjunction with the diet's conditions, along with the skill of the healer guiding the intervention. Further, a detailed risk assessment revealed sophisticated safety measures and tools designed to address adverse responses. The importance of adequate training of the healer that administers the diet was particularly highlighted in this context.

CONCLUSIONS

The dieta is a central therapeutic concept and tool in Peruvian-Amazonian traditional medicine and a unique method for using psychoactive plants. Multidisciplinary health research that includes traditional treatment methods from Indigenous cultures, Amazonian and other, should not be neglected in the current global interest in psychedelic therapies; such research may in the long-term contribute to a more inclusive psychedelic research paradigm as well as healthcare practice in countries where rich traditional healing systems exist, and perhaps beyond. It may also contribute to the recognition of the Indigenous healers as not only historical forerunners, but also current leading experts in psychedelic medicine.

Azepine-Indole Alkaloids From Psychotria nemorosa Modulate 5-HT2A Receptors and Prevent in vivo Protein Toxicity in Transgenic Caenorhabditis elegans

Nemorosine A (1) and fargesine (2), the main azepine-indole alkaloids of Psychotria nemorosa, were explored for their pharmacological profile on neurodegenerative disorders (NDs) applying a combined in silico-in vitro-in vivo approach. By using 1 and 2 as queries for similarity-based searches of the ChEMBL database, structurally related compounds were identified to modulate the 5-HT2A receptor; in vitro experiments confirmed an agonistic effect for 1 and 2 (24 and 36% at 10 μM, respectively), which might be linked to cognition-enhancing properties. This and the previously reported target profile of 1 and 2, which also includes BuChE and MAO-A inhibition, prompted the evaluation of these compounds in several Caenorhabditis elegans models linked to 5-HT modulation and proteotoxicity. On C. elegans transgenic strain CL4659, which expresses amyloid beta (Aβ) in muscle cells leading to a phenotypic paralysis, 1 and 2 reduced Aβ proteotoxicity by reducing the percentage of paralyzed worms to 51%. Treatment of the NL5901 strain, in which α-synuclein is yellow fluorescent protein (YFP)-tagged, with 1 and 2 (10 μM) significantly reduced the α-synuclein expression. Both alkaloids were further able to significantly extend the time of metallothionein induction, which is associated with reduced neurodegeneration of aged brain tissue. These results add to the multitarget profiles of 1 and 2 and corroborate their potential in the treatment of NDs.

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.

Ayahuasca as a Decoction Applied to Human: Analytical Methods, Pharmacology and Potential Toxic Effects

Ahyahuasca is a term commonly used to describe a decoction prepared by cooking the bark or crushed stems of the liana Banisteriopsis caapi (contains β-carbolines) alone or in combination with other plants, most commonly leaves of the shrub Psychotria viridis (contains N,N-dimethyltryptamine-DMT). More than 100 different plants can serve as sources of β-carbolines and DMT, which are the active alkaloids of this decoction, and therefore it is important to know the most accurate composition of the decoction, especially when studying the pharmacology of this plant. The aim was to summarize the latest sensitive methods used in the analysis of the composition of the beverage itself and the analysis of various biological matrices. We compared pharmacokinetic parameters in all of the studies where decoction of ayahuasca was administered and where its composition was known, whereby minimal adverse effects were observed. The therapeutic benefit of this plant is still unclear in the scientific literature, and side effects occur probably on the basis of pre-existing psychiatric disorder. We also described toxicological risks and clinical benefits of ayahuasca intake, which meant that the concentrations of active alkaloids in the decoction or in the organism, often not determined in publications, were required for sufficient evaluation of its effect on the organism. We did not find any post-mortem study, in which the toxicological examination of biological materials together with the autopsy findings would suggest potential lethality of this plant.

Hallucinogenic drugs and their potential for treating fear-related disorders: Through the lens of fear extinction

Fear-related disorders, mainly phobias and post-traumatic stress disorder, are highly prevalent, debilitating disorders that pose a significant public health problem. They are characterized by aberrant processing of aversive experiences and dysregulated fear extinction, leading to excessive expression of fear and diminished quality of life. The gold standard for treating fear-related disorders is extinction-based exposure therapy (ET), shown to be ineffective for up to 35% of subjects. Moreover, ET combined with traditional pharmacological treatments for fear-related disorders, such as selective serotonin reuptake inhibitors, offers no further advantage to patients. This prompted the search for ways to improve ET outcomes, with current research focused on pharmacological agents that can augment ET by strengthening fear extinction learning. Hallucinogenic drugs promote reprocessing of fear-imbued memories and induce positive mood and openness, relieving anxiety and enabling the necessary emotional engagement during psychotherapeutic interventions. Mechanistically, hallucinogens induce dynamic structural and functional neuroplastic changes across the fear extinction circuitry and temper amygdala's hyperreactivity to threat-related stimuli, effectively mitigating one of the hallmarks of fear-related disorders. This paper provides the first comprehensive review of hallucinogens' potential to alleviate symptoms of fear-related disorders by focusing on their effects on fear extinction and the underlying molecular mechanisms. We overview both preclinical and clinical studies and emphasize the advantages of hallucinogenic drugs over current first-line treatments. We highlight 3,4-methylenedioxymethamphetamine and ketamine as the most effective therapeutics for fear-related disorders and discuss the potential molecular mechanisms responsible for their potency with implications for improving hallucinogen-assisted psychotherapy.

Pharmahuasca and DMT Rescue ROS Production and Differentially Expressed Genes Observed after Predator and Psychosocial Stress: Relevance to Human PTSD

Post-traumatic stress disorder (PTSD) is associated with cognitive deficits, oxidative stress, and inflammation. Animal models have recapitulated features of PTSD, but no comparative RNA sequencing analysis of differentially expressed genes (DEGs) in the brain between PTSD and animal models of traumatic stress has been carried out. We compared DEGs from the prefrontal cortex (PFC) of an established stress model to DEGs from the dorsolateral PFC (dlPFC) of humans. We observed a significant enrichment of rat DEGs in human PTSD and identified 20 overlapping DEGs, of which 17 (85%) are directionally concordant. N,N-dimethyltryptamine (DMT) is a known indirect antioxidant, anti-inflammatory, and neuroprotective compound with antidepressant and plasticity-facilitating effects. We tested the capacity of DMT, the monoamine oxidase inhibitor (MAOI) harmaline, and "pharmahuasca" (DMT + harmaline) to reduce reactive oxygen species (ROS) production and inflammatory gene expression and to modulate neuroplasticity-related gene expression in the model. We administered DMT (2 mg/kg IP), harmaline (1.5 mg/kg IP), pharmahuasca, or vehicle every other day for 5 days, following a 30 day stress regiment. We measured ROS production in the PFC and hippocampus (HC) by electron paramagnetic resonance spectroscopy and sequenced total mRNA in the PFC. We also performed in vitro assays to measure the affinity and efficacy of DMT and harmaline at 5HT_2AR compared to 5-HT. DMT and pharmahuasca reduced ROS production in the PFC and HC, while harmaline had mixed effects. Treatments normalized 9, 12, and 14 overlapping DEGs, and pathway analysis implicated that genes were involved in ROS production, inflammation, growth factor signaling, neurotransmission, and neuroplasticity.

Ayahuasca may help to improve self-compassion and self-criticism capacities

OBJECTIVE

Ayahuasca is a psychedelic brew that originated in the Amazon basin. The psychological effects of this drug are becoming better understood due to the growing research interest in identifying new potential therapeutic agents for the treatment of emotion dysregulation and other disorders. Previous studies suggest that ayahuasca enhances mindfulness-related capacities (decentering, non-judging, non-reacting and acceptance) and emotion regulation. The aim of the present exploratory study was to determine the effects of ayahuasca on self-compassion in a community sample.

METHODS

We administered validated questionnaires (the Self-Compassion Scale-Short Form and Forms of Self-Criticism and Self-Reassurance) to evaluate pre-post changes in self-compassion and self-criticism/self-reassurance in 45 volunteers (27 women; 60%) before and after (≤24 h) an ayahuasca ceremony. Most participants (n = 29; 67.4%) had previously used ayahuasca.

RESULTS

Ayahuasca resulted in significant improvements, with medium to large effect sizes (η²  = 0.184-0.276), in measures of self-compassion (p < 0.05), self-criticism (p < 0.01) and self-reassurance (p < 0.01).

CONCLUSIONS

The findings of this study suggest that ayahuasca promotes well-being and self-compassion, which could have a therapeutic effect on individuals with negative affect and other psychopathological conditions. Large, controlled studies are needed to confirm these findings.

Psilocybin use is associated with lowered odds of crime arrests in US adults: A replication and extension

BACKGROUND

The United States boasts the largest prison population in the world, conferring significant direct and indirect costs (e.g. lost wages for the incarcerated, increased morbidity/mortality, etc.) to society. Recidivism rates are high for the imprisoned and most interventions to reduce criminality are minimally effective. Thus, in addition to the need for criminal justice reform, there is a need to better understand factors linked to lowered criminal behavior.

AIM

The aim of this study was to assess the relationships between the use of classic psychedelic substances (psilocybin, LSD, peyote, and mescaline) and past year arrests for various crimes (i.e. property, violence, alcohol and substance use, miscellaneous crimes).

METHODS

This study used nationally representative data from The National Survey on Drug Use and Health (NSDUH) (2015-2019) (N = 211,549) to test the aforementioned associations.

RESULTS

Lifetime psilocybin use was associated with lowered odds of seven of 11 past year arrest variables (adjusted odds ratio (aOR) range = 0.30-0.73). Peyote was associated with reduced odds of motor vehicle theft (aOR = 0.30) and driving under the influence (aOR = 0.52), and mescaline was associated with reduced odds of drug possession/sale (aOR = 0.51). Virtually all other substances either shared no relationship to our outcomes or conferred higher odds of arrest.

CONCLUSION

This study suggests that use of classic psychedelic substances is associated with lowered odds of crime arrests. Future research should explore whether causal factors and/or third variable factors (e.g. personality, political orientation) underlie the relationship between classic psychedelic use and reduced criminal behavior.

How to account for hallucinations in the interpretation of the antidepressant effects of psychedelics: a translational framework

RATIONALE

Recent trials with psychedelics in major depressive disorder and treatment-resistant depression showed remarkable improvements in depressive symptoms that can last for up to several months after even a single administration. The lack of an appropriate placebo control group-as patients are often able to discriminate the subjective effects of the drug-and an incomplete understanding of the role of the hallucinogenic and mystical experience, hampers the interpretation of these therapeutic effects.

OBJECTIVES

To control for these factors, we developed a translational framework based on establishing pharmacokinetic/pharmacodynamic (PK/PD) relationships in rodents and humans for hallucinogenic (i.e., discriminative stimulus effects in rodents and humans; head twitch responses in rodents; questionnaires in humans) and therapeutic effects. For the latter, we selected the pattern separation and attentional set-shifting tasks as measures for cognitive flexibility because of their high translational value. We predict that these PK/PD analyses will lead to a more objective evaluation of improvements in patients compared to relying only on the currently used self-reported questionnaires. We hypothesize that-if the role of the hallucinogenic experience is not central in the antidepressant effects of psychedelics-the ED₅₀'s for the therapeutic effects will be significantly lower than for the hallucinogenic and mystical effects.

CONCLUSION

Our framework will help to inform future studies that aim at the elucidation of the mechanism(s) of action of psychedelics in depression, and the role of the acute subjective and/or hallucinogenic experience in their effects.

Psychosocial and Drug Use Assessment of Regular vs. Non-Regular Ayahuasca Users in a Brazilian Sample: a Web-Based Survey

Background: Preliminary evidence suggests that long-term ayahuasca use is associated with better psychosocial outcomes and less drug use; however, available data on the association between ayahuasca intake frequency and psychosocial outcomes is limited. Objectives: We sought to characterize and investigate the association of regular ayahuasca use, as compared to non-regular use, on licit (alcohol and tobacco) and illicit (cannabis, psychostimulants, psychedelics, and non-medical opioids) drug use and psychosocial outcomes. Methods: An online-based cross-sectional survey was taken among people who use ayahuasca in Brazil assessing sociodemographic, drug and ayahuasca use, anxiety and depression (HAD-S), intrinsic religiosity (IRI), negative and positive affects (PANAS), satisfaction with life (SWLS), and five quality of life domains (WHOQOL-Brief). Multivariate regressions for each psychosocial outcome and drug use were performed comparing regular to non-regular ayahuasca users while correcting for sociodemographic variables. Results: A total of 286 valid answers were retrieved, divided into people with regular (n = 101) and non-regular (n = 185) ayahuasca use. Groups had similar sociodemographic profiles and lifetime use of drugs. In the multivariate analysis, regular use of ayahuasca was associated with lower anxiety (B: -0.97), negative affect (B: -2.62), general (B: 0.22) and physical (B: 0.17) quality of life, higher intrinsic religiosity scores (B: 4.16), and less past-month licit (OR = 0.30) and illicit (OR = 0.49) use of substances. Conclusions: Our results show that ceremonial regular ayahuasca compared to non-regular use is associated with better psychosocial and mental health outcomes and less drug use. Studies with repeated ayahuasca administration and extended follow-ups are essential to clarify the nature of ayahuasca's therapeutic effects and to guide future clinical research.