Abstract
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.