Small clinical trials (notably from Brazil, 2016–2019) show rapid and sustained antidepressant effects in treatment-resistant depression after a single dose. Sample sizes are still small; larger phase 2 and 3 trials are underway. It is promising, not proven.

For medically screened, non-medicated adults in a proper container, ayahuasca has a strong safety record. Risks concentrate in medication interactions (SSRIs, MAOIs), pre-existing cardiac conditions, and psychosis-spectrum diagnoses — which is why screening exists.

The evidence base is small but growing. Observational and early clinical studies suggest meaningful effects on depression, PTSD, addiction, and end-of-life anxiety, alongside sustained increases in wellbeing and mindfulness. The strongest signals come from work by Palhano-Fontes, Osório, dos Santos, and the Beckley/ICEERS teams. Big caveats: sample sizes are small, most participants self-select, long-term data is thin, and the ceremonial context (which the research usually can't isolate) is a huge variable.