Single Dose of DMT, Ayahuasca's Active Ingredient, Eases Depression in Phase IIa Trial
A phase IIa trial found that a single dose of DMT, the active ingredient in ayahuasca, improved depressive symptoms in adults with depression. The small, randomized study showed effects lasting up to three months, with mainly mild adverse effects. Experts call the results promising but preliminary.
A single dose of dimethyltryptamine (DMT), the active ingredient in ayahuasca, improved depressive symptoms in adults with depression, according to results of a phase IIa clinical trial published in Nature Medicine. The trial included 34 people, 17 of whom received intravenous DMT, and this group showed greater improvements in depressive symptoms than the control group. After two weeks, DMT was administered to all participants, and the antidepressant effects lasted for three months.
This is the first clinical trial to specifically evaluate the efficacy of DMT for major depressive disorder, though previous evidence supported the safety and antidepressant effects of DMT-containing compounds such as ayahuasca. The intervention consists of a brief 10-minute infusion, accompanied only by a preparation session and an integration session, with acute psychedelic effects lasting around 30 minutes. This design greatly facilitates large-scale implementation compared to other psychedelic therapies, such as psilocybin, which require patients to remain under observation for up to eight hours and multiple preparation and integration sessions.
The results showed a significant improvement in depressive symptoms, already observed from the first week and sometimes lasting up to six months. Adverse effects were mainly pain at the injection site, nausea, and transient anxiety. However, the study has serious limitations: the sample size is small (17 patients per arm), and the open-label design only allowed efficacy to be evaluated against placebo for two weeks, as all patients received a second dose afterward. While the subsequent improvement was maintained for up to three months, the contribution of the placebo effect or other contextual factors cannot be determined. Numerical differences between patients who received one dose and those who received two did not reach statistical significance.
Experts noted that the study is a randomized, double-blind, placebo-controlled trial with rigorous selection and clinical evaluation procedures, giving it greater methodological robustness than many preliminary psychedelic studies. It uses validated clinical measures and temporal follow-up, allowing observation of immediate and longer-term effects over 3–6 months. Nevertheless, it is not yet a large-scale confirmatory trial, so results should be interpreted as promising but preliminary. If verified in larger trials, this approach could lead to brief interventions that facilitate access to these therapies and their implementation in public health systems.