Ayahuasca is a psychoactive plant brew containing dimethyltryptamine (DMT) and monoamine oxidase inhibitors (MAOIs). It originates from the Amazon basin, where it is used primarily for ceremonial purposes. Ayahuasca tourists are now entering certain communities seeking alternative physical or psychological healing, as well as spiritual growth. Rationale Recent evidence has shown that the similar acting psychedelic compound, psilocybin, facilitated long-term increases in trait openness following a single administration. Objectives This paper assesses the impact of ayahuasca on personality in a traditional framework catering for ayahuasca tourists. Method Within a mixed design, we examined the effect of ayahuasca on participants’ personality (measured by the NEO Personality Inventory 3 questionnaire) across time (pre- to post-ayahuasca administration, and 6-month follow-up), relative to a comparison group (who did not ingest ayahuasca). Results The results demonstrated significant increases in agreeableness pre- and post-ayahuasca administration and significant reductions in neuroticism in 24 participants, relative to the comparison group. Both of these changes were sustained at 6-month follow-up, and trait level increases were also observed in openness at this stage. Additionally, greater perceived mystical experience (measured using the Mystical Experience Questionnaire 30) was associated with increased reductions in neuroticism. Conclusions These findings, which indicate a positive mediating effect of ayahuasca on personality, support the growing literature suggesting potential therapeutic avenues for serotonergic psychedelics.

Ayahuasca is a natural psychoactive brew, used in traditional ceremonies in the Amazon basin. Recent research has indicated that ayahuasca is pharmacologically safe and its use may be positively associated with improvements in psychiatric symptoms. The mechanistic effects of ayahuasca are yet to be fully established. In this prospective naturalistic study, 63 self-selected participants took part in ayahuasca ceremonies at a retreat centre in the Peruvian Amazon. Participants undertook the Beck Depression Inventory (BDI-II), State-Trait Anxiety Inventory (STAI), Self-compassion Scale (SCS), Clinical Outcomes in Routine Evaluation-Outcome Measure (CORE-OM), as well as secondary measures, pre- and post-retreat and at 6-months. Participants also provided saliva samples for pre/post epigenetic analysis. Overall, a statistically significant decrease in BDI-II (13.9 vs. 6.1, p < 0.001), STAI (44.4 vs. 34.3 p < 0.001) scores, and CORE-OM scores were observed (37.3 vs. 22.3 p < 0.001) at post-retreat, as well as a concurrent increase in SCS (3.1 vs. 3.6, p < 0.001). Psychometric improvements were sustained, and on some measures values further decreased at 6-month follow-up, suggesting a potential for lasting therapeutic effects. Changes in memory valence were linked to the observed psychometric improvements. Epigenetic findings were equivocal, but indicated that further research in candidate genes, such as sigma non-opioid intracellular receptor 1 (SIGMAR1), is warranted. This data adds to the literature supporting ayahuasca's possible positive impact on mental health when conducted in a ceremonial context. Further investigation into clinical samples, as well as greater analyses into the mechanistic action of ayahuasca is advised.

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 this brew and describe recent work on its pharmacology and phenomenological responses to, and clinical applications of ayahuasca. There has been a significant increase in interest surrounding ayahuasca since the turn of the millennium. Increasing numbers of tourists are travelling to the Amazon rainforest to drink the brew, with various media outlets, celebrities, and researchers describing benefits from its consumption. Ayahuasca is now present across the globe and retreat centres offering plant medicine experiences has become a thriving business. Anecdotal evidence varies significantly, ranging from evangelical accounts to horror stories involving physical and psychological harm. The effects of the brew on personality, mental health outcomes, and nature-relatedness are discussed in this review. Further, 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 its therapeutic uses.

Indigenous Amazonian shamanic ayahuasca practice is deeply rooted in nature and it is employed as an ecological mediating agent and in collective environmental decision-making processes by some of the groups that use it. Phenomenologically, the ayahuasca experience is often rich in nature-based themes and content, and its usage has been associated with eliciting shifts in perspectives and attitudes towards nature. In this proof of concept study, participation in an ayahuasca retreat in a traditional indigenous Amazonian context (with a mean of 5.85 ceremonies attended) was associated with significant increases in nature relatedness (n = 24; Cohen’s d = .51) and mindfulness (n = 38; Cohen’s d = .75), and improvements in depression (n = 47; Cohen’s d = 1.18), state anxiety (n = 47; Cohen’s d = 1.02), and trait anxiety (n = 42; Cohen’s d = .88). Furthermore, significant negative correlations were found between changes in nature relatedness and depression (r = .623, p = .001), state anxiety (r = -.542, p = .008), and trait anxiety (r = -.485, p = .022), with a significant positive correlation between change in nature relatedness and mindfulness (r = .747, p = .001). It is currently unclear if the changes seen were due to consumption of the brew, participation in ceremony, or the retreat setting itself. Although this pilot study suggests a potential therapeutic role for Amazonian ayahuasca retreats as a multidimensional intervention, further work is required to assess the role of possible mediators underlying such shifts, while evaluating to what extent these are sustained long-term.