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About this resource
This page introduces a 2015 preliminary report in which 6 inpatients experiencing a current episode of recurrent depression received a single ayahuasca intervention in a research setting and were followed with depression scales afterward. It was an early clinical resource that led toward later randomized trials, but it had no control group and included very few participants.
Study design
Participants received clinical assessment before the intervention and were reassessed with several depression scales at 1, 7, and 21 days afterward, among other time points. It was an open-label design in which everyone knew about the intervention, with no comparison against placebo, usual treatment, or another drug. Researchers also observed acute effects and safety.
Content
Against the background of the time conventional antidepressants may take to act and treatment resistance, the authors explored the possibility of rapid symptom change. The research preparation was chemically analyzed and administered under supervision in an inpatient setting. These conditions differ from diverse brews in circulation and unsupervised environments.
Several scales were used to assess depression, with each post-intervention time point compared against baseline. In a small exploratory study, even statistically significant findings may have unstable effect sizes, and a change in 1 participant can substantially alter the average.
Results
The authors reported large decreases in depression scores from baseline, with reductions of up to approximately 82% depending on the scale and time point. Some changes were observed through day 21. Nausea, vomiting, and perceptual and emotional changes were recorded during the acute phase.
Without a control group, however, the findings cannot be distinguished from natural recovery, the inpatient environment, expectations, contact with researchers, repeated assessment, or regression to the mean. Observing a large change in 6 people provides a reason for subsequent research but does not establish efficacy.
Limitations
The study included 6 participants and was unblinded, nonrandomized, and uncontrolled. Participant selection and the inpatient setting also limit generalizability. Analyses across multiple scales and time points and the short follow-up may lead to overestimation of chance changes or persistence. The study has no power to detect rare adverse events.
Because both participants and raters knew about the intervention, expectations and observer bias cannot be separated. Selecting people with high baseline scores can produce regression to the mean, in which scores decrease at the next assessment through natural variation alone. Results from 6 people also cannot provide stable estimates of responder characteristics or nonresponse rates.
Safety
The absence of serious problems in a small controlled research setting would not establish general safety. Cardiovascular responses, vomiting, acute anxiety, psychosis-like or manic reactions, drug interactions, and pregnancy require separate evaluation. If patients with depression discontinue existing medication on their own, both interactions and worsening of their condition may be concerns.
A short-term average decrease in symptoms does not replace the full course of each participant or assessment of suicide-related risk. Acute worsening or crisis in depression requires appropriate clinical evaluation and continuing support rather than reliance on a research article.
This study is hypothesis-generating evidence, not a basis for an individual to replace existing treatment. Later controlled trials also retain limitations in sample size and follow-up, so evidence needs to be weighted according to each study design.
Source and rights
Original source: Osório FL, et al. Antidepressant effects of a single dose of ayahuasca in patients with recurrent depression: a preliminary report. Revista Brasileira de Psiquiatria. 2015;37(1):13–20. DOI: 10.1590/1516-4446-2014-1496.
This page is a detailed introduction based on publicly available bibliographic information and the abstract; it is not a translation or republication of the original article. Consult the original for precise eligibility criteria, scales, numbers, and statistics.