A Clinical Trial of Tolcapone in Obsessive Compulsive Disorder

The primary aim of the present study is to examine the efficacy and safety of tolcapone in adults with moderate to severe OCD.

Inclusion Criteria: 1. Men and women age 18-65 years 2. Primary diagnosis of OCD 3. YBOCS score of at least 21 at baseline (moderate or higher severity) 4. Ability to understand and sign the consent form Exclusion Criteria: 1. Unstable medical illness based on history or clinically significant abnormalities on baseline physical examination 2. Current pregnancy or lactation, or inadequate contraception in women of childbearing potential 3. Subjects considered an immediate suicide risk based on the Columbia Suicide Severity rating Scale (C-SSRS) (www.cssrs.columbia.edu/docs) 4. History of psychosis or bipolar disorder based on DSM-5 criteria 5. Alcohol/substance use disorder and/or illegal substance use based on urine toxicology 6. Initiation of psychological interventions within 3 months of screening (those who are continuing with CBT will be included) 7. Use of any new psychotropic medication within 3 months of study entry (stable doses of psychotropics will be allowed) 8. Major cognitive impairment that interferes with the capacity to understand and self-administer medication or provide written informed consent 9. Abnormal liver function tests at baseline 10. MADRS \>30 at baseline