Psilocybin mushrooms show promise as a treatment for obsessive-compulsive disorder (OCD), a condition where people experience unwanted intrusive thoughts and compulsive behaviors. Current standard treatments with antidepressants don’t work for many patients and take weeks to show effects. Early research suggests psilocybin may reduce OCD symptoms quickly and works in treatment-resistant cases, though more rigorous studies are needed to confirm its effectiveness and understand how it works in the brain.