Psilocybin holds promise as an add-on treatment for patients with alcohol use disorder, halving heavy drinking days compared with placebo in a novel trial, psychiatrists say.

The addition of two sessions of psychedelic drug therapy to 12 weeks of psychotherapy produced superior outcomes to talking therapies alone, they found in the double-blinded, randomised trial of 95 patients.

During eight months of follow-up, the percentage of heavy drinking days dropped to 10% for those whose treatment included a psilocybin capsule and to 24% for the control group, who received an identical capsule containing an active placebo, the antihistamine diphenhydramine. 

In addition, among those taking the hallucinogen the average daily alcohol consumption was lower and the proportion of ‘no heavy drinking days’ was higher than controls, the researchers reported in JAMA Psychiatry.