Feasibility, Clinical Effects, and Safety of Psilocybin-assisted Psychotherapy for Treatment-resistant OCD

This study tests whether psilocybin-assisted psychotherapy (a structured therapy session guided by a therapist, combined with a controlled dose of psilocybin, the compound in psychedelic mushrooms) is feasible and safe for people with treatment-resistant OCD — meaning OCD that has not responded to standard medications and therapy. **You may be eligible if...** - You are 18–65 years old with a confirmed diagnosis of OCD - Your OCD symptoms are moderate to severe and have not improved after trying at least 2 different medications and at least one course of cognitive behavioural therapy (CBT) - You can read and communicate in English - You are an outpatient and able to give informed consent - You are willing to use effective contraception if you could become pregnant **You may NOT be eligible if...** - You have a personal or family history of psychosis, bipolar disorder type 1, or schizophrenia - You are currently pregnant or breastfeeding - You have significant kidney impairment - You have abnormal blood test results at screening Talk to your doctor to see if this trial is right for you.