Two doses of psilocybin, given alongside psychotherapy, substantially reduced heavy drinking in people with alcohol use disorder compared to an active placebo (diphenhydramine) plus psychotherapy. Over 32 weeks, heavy drinking days averaged 9.7% in the psilocybin group versus 23.6% in the placebo group—a mean difference of 13.9 percentage points. Daily alcohol consumption was also lower with psilocybin. No serious adverse events occurred in the psilocybin group. The findings support further research into psilocybin-assisted treatment for alcohol use disorder.
An open-label extension of a Phase II randomized controlled trial examined the safety and efficacy of psilocybin-assisted therapy for alcohol use disorder. Participants who had received either psilocybin or placebo in the main trial were offered two open-label psilocybin sessions. The treatment was well tolerated, with no serious adverse events attributed to psilocybin. Heavy drinking days decreased substantially from baseline, and the reduction was sustained through the 32-week follow-up. The findings suggest that psilocybin-assisted therapy may produce durable reductions in alcohol consumption among individuals with alcohol use disorder.