Background: The global use of ayahuasca, a psychoactive Amazonian brew containing N, N-dimethyltryptamine, is increasing significantly. This prospective cohort study characterized an international cohort of ayahuasca users and the relationship between ritual ayahuasca use and its association with reported side effects, substance use patterns, mental health, and physical health outcomes. Preliminary findings from a subset of depressed individuals within this cohort were presented at MAPS 2023. This report presents the final analysis.Methods: A total of 20 ayahuasca groups were identified through snowball sampling. Recruitment was stratified by depression, anxiety, and neither condition using validated screening tools. Facilitators distributed anonymized links to a series of four surveys administered at 1-week pre-ceremony, 24-hours post-ceremony, 1-month post-ceremony, and 6-months post-ceremony. Descriptive statistics and repeated measures analyses were conducted using SAS and R.Results: 224 participants were enrolled in the following categories: 129 with depression, 101 with anxiety, and 91 with neither; of note, 90 had both depression and anxiety. There was a 26% loss to follow-up at 6-months. The majority were naïve users, and 59% participated in a Shipibo ceremony. Persistent side effects were reported by 5% of participants during the 1-month follow-up, including nausea, diarrhea, lightheadedness, and headaches. Around 7% experienced persistent visual hallucinations. Participants were surveyed about chronic health issues during the presurvey and asked at a 1-month follow-up about any symptom improvement they attributed to their participation in the ayahuasca ceremony. Among respondents, all five individuals with back pain reported improvement at 1 month, with one individual reporting resolution of pain. Similarly, all three individuals with inflammatory bowel disease reported symptom improvement, with one reporting a significant change. Five out of six individuals with chronic fatigue syndrome experienced improvement, as did two of four individuals with migraines. Of the eight individuals with thyroid disease, the majority did not report any change.Statistically significant reductions were observed in depression, state and trait anxiety scores, and quality of life from pre-ceremony data to the 1- and 6-month data, (p>0.001) using mixed-effects modeling without covariates. Additional measures currently under analysis include validated scales evaluating problematic substance use, the mystical experience, connectedness to nature, mindfulness, somatic awareness, and personality measures – these data and related analyses will be included in our presentation.Discussion: Ceremonial ayahuasca use in a variety of practice settings with both indigenous and non-indigenous facilitators is significantly associated with transdiagnostic improvements in mental health symptoms and quality of life. There are also anecdotal reports of improvement across several self-reported symptoms of chronic physical health conditions, with rare reports of illness worsening post-ceremony. Further research is needed to understand the physical and psychospiritual mechanisms that are impacted by ceremonial ayahuasca use and to better understand the role of varying ceremonial contexts in this work.
