Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder: A Randomized Clinical Trial
How much of this benefit could come from expectancy and intensive therapist contact rather than the drug itself?
Well-supported by good-quality research. how we score evidence
Caveat on this rating: Waitlist-controlled (no placebo), very small N, single site with strong psychedelic-research identity; effect sizes this large rarely survive larger placebo-controlled replication.
Phase 3 complete; rolling NDA under FDA review, final module expected Q4 2026. Breakthrough Therapy designation 2018 (TRD) / 2019 (MDD).
In 27 adults with major depression randomized to immediate vs delayed (8-week waitlist) psilocybin-assisted therapy, 71% showed clinically significant response at weeks 1 and 4 after treatment and 54-58% met remission criteria — but the waitlist control cannot separate drug effects from expectancy.
Worth asking
How much of this benefit could come from expectancy and intensive therapist contact rather than the drug itself?
Source
Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder: A Randomized Clinical Trial — Davis AK, et al. (2021)
Top-tier peer-reviewed journal
Read the source: https://doi.org/10.1001/jamapsychiatry.2020.3285
DOI: 10.1001/jamapsychiatry.2020.3285
How this was scored
- Study design
- Randomised controlled trial
- Funding
- Independently funded
- Published in
- Top-tier peer-reviewed journal
- Sample size
- 27
- Preregistered
- Yes
- Conflicts disclosed
- Yes
- Independent of proponent
- No
- Retracted
- No
Read the full scoring rubric, including what it can't tell you.
Published August 19, 2026.
Questions
How strong is the evidence behind this?
Resolv rates this source "strong evidence". Well-supported by good-quality research. It scores 75 out of 100 on our published rubric. One caveat travels with that badge: Waitlist-controlled (no placebo), very small N, single site with strong psychedelic-research identity; effect sizes this large rarely survive larger placebo-controlled replication. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder: A Randomized Clinical Trial — Davis AK, et al. (2021). Published in: Top-tier peer-reviewed journal. DOI: 10.1001/jamapsychiatry.2020.3285. The full source is linked on this page so you can read it yourself.
Who paid for this research, and does that matter?
Study design: Randomised controlled trial. Funding: Independently funded. The researchers were not independent of whoever benefits from the result. Industry sponsorship is one of the most reliably measured biases in medicine, which is why funding carries real weight in the score rather than sitting in a footnote.
Is psilocybin FDA approved for this use?
No. Its current status is: Phase 3 trials. Phase 3 complete; rolling NDA under FDA review, final module expected Q4 2026. Breakthrough Therapy designation 2018 (TRD) / 2019 (MDD).
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.