Research library / Clinical trial
Rapid antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression: a randomized placebo-controlled trial
Palhano-Fontes F, Barreto D, Onias H, et al. Psychological Medicine 2019;49(4):655-663
This trial was described by its authors as the first placebo-controlled test of a psychedelic in treatment-resistant depression. Twenty-nine patients received one dose of ayahuasca, a traditional Amazonian brew containing DMT, or a placebo, without knowing which. Depression was rated one, two and seven days later. The ayahuasca group did significantly better at every point, and the gap widened by day seven, when about two thirds had responded compared with about a quarter on placebo. Remission rates also leaned towards ayahuasca but did not quite reach significance. The study was small and followed people for only a week, so it says nothing about lasting benefit. It does provide controlled evidence that a single supervised dose can have a fast antidepressant effect.
What it found
- MADRS depression scores were significantly lower with ayahuasca than placebo at days 1, 2 and 7
- Between-group effect size grew from d = 0.84 (days 1-2) to d = 1.49 (day 7)
- Day-7 response: 64% vs 27%; remission 36% vs 7% (a trend, p = 0.054)