Review: psychedelic treatments in psychiatry still count as experimental

The question

How strong is the clinical evidence for using psychedelics and related drugs to treat psychiatric conditions such as depression and post-traumatic stress disorder (PTSD)?

What they did

The authors reviewed the psychiatric psychedelic literature of the past five years, including randomized controlled trials and pooled analyses in mood disorders, treatment-resistant depression and PTSD. They discussed psilocybin, MDMA (the drug also known as ecstasy), LSD and ayahuasca. They then judged the overall certainty of the evidence using an international grading system.

What they found

The authors report that psilocybin produces consistent and often large improvements in major depressive disorder, but that in the most rigorous trials the pre-specified main outcome does not always reach statistical significance. They note that a synthetic psilocybin (COMP360) met its primary endpoint in two phase 3 trials in 2025-2026, which they call the most advanced regulatory evidence so far. MDMA-assisted psychotherapy has the largest phase 3 dataset in PTSD, yet in 2024 the US Food and Drug Administration declined to approve the product on ethical grounds. Evidence for LSD and ayahuasca in depression and anxiety is described as considerably weaker. Overall certainty was rated low or very low for several indications, mainly because participants and staff can usually tell who received the drug, samples are small, trials differ from each other, and long-term safety data are lacking.

The fine print

This is a narrative review, not a systematic review or meta-analysis, so the selection of studies and the grading reflect the authors’ judgment. No participant numbers, effect sizes or pooled results are given in the abstract. Conclusions about specific trials cannot be checked from the abstract alone, and this summary is based on the abstract only.

What it means

Psychedelic treatments show consistent and sometimes strong effects in psychiatric trials, but the authors argue that methodological problems mean psilocybin and the classic psychedelics should still be viewed as experimental rather than established treatments.

Evidence grade: Low. This is a narrative review article that summarizes other people’s trials rather than reporting new data or a formal pooled analysis.

This summary is based on the study’s published abstract.