Schedule of Events | Symposia

Psilocybin-Assisted Therapy for Relapse Prevention in Alcohol Use Disorder: A randomized control trial

Poster Session E - Monday, March 31, 2025, 2:30 – 4:30 pm EDT, Back Bay Ballroom/Republic Ballroom

Nathalie M. Rieser^1,2 (nathalie.rieser@bli.uzh.ch), Raoul Bitar¹, Simon Halm¹, Christina Rossgoderer¹, Ladina P. Gubser¹, Maeva Thevenaz¹, Yara Kreis¹, Robin von Rotz¹, Carlos Nordt¹, Flora Moujaes¹, Etna J.E. Engeli¹, Andres Ort¹, Erich Seifritz¹, Franz X. Vollenweider¹, Marcus Herdener¹, Katrin H. Preller¹; ¹Psychiatric University Hospital Zurich, ²Johns Hopkins University

Background: Psilocybin has shown promising therapeutic potential; however, its effectiveness in preventing relapse following withdrawal treatment for alcohol use disorder (AUD) remains uncertain. This study assessed whether a single dose of psilocybin, combined with brief psychotherapy, could reduce relapse rates and alcohol use in patients with AUD. Methods: In this single-center, double-blind, randomized clinical trial, we included participants with an AUD who had completed withdrawal treatment within six weeks prior to enrollment. Participants were randomized (1:1) to receive either a single oral dose of psilocybin (25 mg) or placebo (mannitol), in combination with psychotherapy. The primary outcomes were abstinence and mean alcohol use at 4-week follow-up. Outcomes: In total, 37 participants (female:male = 14:23; psilocybin=18, placebo=19) completed the 4-week follow-up. We found no significant differences between groups in abstinence duration (p=0.55; psilocybin mean = 16.8 days; placebo mean = 13.8 days, Cohen’s d=0.15) or mean alcohol use per day (p=0.51; psilocybin median = 0.48 standard alcohol units; placebo median = 0.54, Cohen’s d=0.11) at either 4-week or 6-month follow-up (abstinence: Cohen’s d=0.10; alcohol use: Cohen’s d=0.08). Participants in both groups reported a reduction in craving and temptation to drink alcohol after the dosing visit, with an additional reduction observed in the psilocybin group. Furthermore, we found decrease depression scores and increased quality of life post psilocybin administration, but not placebo. Interpretation: A single dose of psilocybin combined with brief psychotherapy may not be sufficient to reduce relapse rates or alcohol use in patients with AUD following withdrawal treatment.

Topic Area: OTHER