Meta-analysis · 2026
Review of 7 trials finds psilocybin therapy reduces depression scores; setup details less clear
- Original title
- Methodological moderators of psilocybin-assisted therapy in depression: A systematic review and meta-analysis.
- Authors
- Syed OA, Tsang B, Nestor SM, et al.
- Journal
- Neuroscience and biobehavioral reviews, 2026
- Molecules
- Psilocybin
- Conditions
- Depression
- Participants
- 522
- Evidence grade
- Moderate
- Source
- Read the original paper
The question
Does psilocybin-assisted therapy reduce depression symptoms, and do the details of how trials are run — dosing method, session length, style of therapy — change how well it works?
What they did
Researchers searched four research databases (PubMed, MEDLINE, PsychInfo and Embase) for randomized controlled trials that used psilocybin-assisted therapy for major depressive disorder. Seven trials with a total of 522 participants met the criteria. They pooled the change in depression scores from before to after treatment, then split the trials into subgroups to compare different study methods.
What they found
Pooling all seven trials, psilocybin-assisted therapy showed a large and statistically significant reduction in depression symptoms compared with control conditions. Subgroup analyses suggested larger effects in trials that adjusted the psilocybin dose to body weight, gave longer preparation, dosing and integration sessions, and used psychotherapy that did not follow a fixed manual. However, the differences between these subgroups were not statistically significant, so they cannot be treated as established.
The fine print
Only seven trials were included, which limits how much can be learned from splitting them into subgroups; the abstract reports no effect sizes, confidence intervals or follow-up lengths. Psilocybin’s noticeable effects make blinding difficult in these trials, which can inflate apparent benefit. The subgroup findings are described as preliminary by the authors themselves. This summary is based on the abstract only.
What it means
Across the randomized trials done so far, psilocybin-assisted therapy was linked to a meaningful drop in depression scores, but which trial methods matter most remains an open question.
Evidence grade: Moderate. A meta-analysis pooling seven randomized controlled trials, but the number of trials is small and the subgroup comparisons were not statistically significant.
This summary is based on the study’s published abstract.