Psilocybin for Treatment of OCD-2

Previous research indicates that psilocybin, a drug that changes activity in brain areas believed to be involved in obsessive-compulsive disorder (OCD), might improve treatment for, and improve lives of, people diagnosed with OCD. The investigators propose to study 20 patients with symptomatic OCD who are not taking mind altering medications or street drugs, to participate in a 12 week study. Participants will be assigned (by luck of the draw) to take low or high dose psilocybin in four dosing sessions separated by 3 weeks. Measurements for the severity of OCD, ability to function, perception of quality of life, safety and tolerability will be measured at baseline prior to drug administration, during the dosing periods, and at the end of study. Other measurements will include brain imaging via fMRI and brain tracing via electroencephalogram (EEG). The investigators believe that during medically supervised dosing sessions, both doses of psilocybin will be safe and well tolerated, and will reduce OCD symptoms. Because psilocybin is a potent drug and especially at the higher dose may induce altered states of consciousness, a thoughtfully implemented procedure for participant safety is in place. Information will be obtained to explore the effects of altered states of consciousness in the outcome of treatment and to find the mechanism of benefit.