A Randomized Controlled Trial of Psilocybin for the Treatment of Obsessive-Compulsive Disorder
Online Publication Service of Würzburg University (Würzburg University) January 1, 2026 Katja Ehrmann
Obsessive Compulsive Disorder (OCD) affects 2-3% of people, causing intrusive thoughts and repetitive behaviors that impair quality of life. Current treatments like cognitive behavioral therapy and SSRIs leave many patients unresponsive. Psilocybin, a psychedelic acting on serotonin receptors, may break rigid neural patterns and reset hyperactive brain networks. In a randomized placebo-controlled trial, participants with severe treatment-resistant OCD received up to 8 doses of psilocybin weekly, with doses varying from low to high. Psilocybin reduced OCD symptoms by 23% to 100%, with improvements lasting weeks to months. Higher doses produced stronger mystical experiences linked to greater symptom reduction. No severe side effects occurred. Despite clinical improvement, no changes in error-related brain activity were observed. Psilocybin appears promising for treatment-resistant OCD in a supportive setting.