Treating Obsessive-Compulsive Disorder with Ketamine

Eligibility Details: Inclusion Criteria for participants with OCD: - age 18-65 - Primary diagnosis of OCD - Sufficient severity of OCD symptoms - ability to tolerate a treatment-free period - capacity to provide informed consent Inclusion criteria for healthy controls: - ages 18-65 - capacity to provide informed consent Exclusion criteria for participants with OCD: - Psychiatric or medical conditions that make participation unsafe - pregnant or nursing females - concurrent use of any medications that might increase the risk of participation (e.g. drug interactions) - presence of metallic device or dental braces Exclusion criteria for healthy controls: - any current or lifetime psychiatric diagnosis - pregnant or nursing females - major medical or neurological problem - presence of metallic device or dental braces