Subjective effects and tolerability of the South American psychoactive beverage Ayahuasca in healthy volunteers.
Level 2 - randomized trial
Single-blind crossover placebo-controlled randomized clinical trial
PubMed 11292011 · doi:10.1007/s002130000606
What was done
Six healthy male volunteers with prior experience using ayahuasca received three increasing doses of encapsulated freeze-dried ayahuasca (0.5, 0.75, and 1.0 mg DMT/kg body weight) or placebo in a single-blind, crossover, placebo-controlled clinical trial. Psychological effects and tolerability were assessed using the Hallucinogen Rating Scale, the Addiction Research Center Inventory, and visual analogue scales.
What was found
Ayahuasca produced significant dose-dependent increases in five of the six subscales of the Hallucinogen Rating Scale, in three scales of the Addiction Research Center Inventory (LSD, MBG, and A), and in visual analogue scales measuring liking, good effects, and high (exact numerical values not reported in abstract). Subjective effects began after 30 to 60 minutes, peaked between 60 and 120 minutes, and resolved by 240 minutes. Cardiovascular tolerability was acceptable, showing a trend toward increased systolic blood pressure. Somatic effects commonly included modified physical sensations and nausea. Five of six volunteers regarded the experience as pleasant, while one volunteer experienced an intensely dysphoric reaction with transient disorientation and anxiety at the medium dose and withdrew from the study.
Why it matters
This study provides early controlled human clinical data on the time course, dose-dependent psychological effects, and safety profile of oral encapsulated ayahuasca.
Limits
The trial had an extremely small sample size (n = 6) and included only healthy male participants with previous ayahuasca experience. The design was single-blind rather than double-blind, and the abstract reports no exact numerical data, variance, or confidence intervals.
Cited by
- context An ayahuasca experience typically lasts between 6 and 8 hours, whereas an ibogaine experience lasts around 72 hours.