•Four trials testing psilocybin for anxiety and depression were meta-analyzed.
• Within-group effects were large (Hedges’ gs = 1.16 to 1.47).•
• Placebo-controlled effects were large (gs = 0.82 to 0.83) across three trials.•
• Potential risk for bias was identified in several domains.
The current meta-analysis examined the effects of psilocybin in combination with behavioral interventions on anxiety and depression in samples with elevated symptoms. Across four studies (one uncontrolled; three randomized, placebo-controlled; N = 117), within-group pre-post and pre-follow-up effects on anxiety and depression were large (Hedges’ gs=1.16 to 1.47) and statistically significant. Across three placebo-controlled studies, pre-post placebo-controlled effects were also large (gs = 0.82 to 0.83) and statistically significant. No serious adverse events were reported. Limitations include the small number of studies and risk for bias within studies. Results tentatively support future research on psilocybin for the treatment of anxiety and depression.
Department of Counseling Psychology, University of Wisconsin – Madison, 335 Education Building, 1000 Bascom Mall, Madison 53706, WI, USA
bDepartment of Educational Psychology, University of Utah, Salt Lake City, UT, USAcVA Palo Alto Health Care System, Palo Alto, CA, USAd
Department of Family Medicine and Community Health, University of Wisconsin – Madison, Madison, WI, USAe
School of Human Ecology, University of Wisconsin – Madison, Madison, WI, USAf
Usona Institute, Fitchberg, WI, USAgSchool of Pharmacy, University of Wisconsin – Madison, Madison, WI, USA
Received 9 April 2019, Revised 22 December 2019, Accepted 1 January 2020, Available online 2 January 2020.