The primary aim of the study is to examine the efficacy and safety of valbenazine in adults with moderate to severe obsessive-compulsive disorder (OCD).

The primary aim of the study is to examine the efficacy and safety of valbenazine in adults with moderate to severe obsessive-compulsive disorder (OCD). Subjects will either receive double-blind valbenazine or inactive placebo for 6 weeks. This will be followed by a 2-week washout period and then 6 weeks of being assigned to the other agent (valbenazine or placebo). The hypothesis to be tested is that valbenazine will significantly improve symptoms of OCD compared to placebo.

Inclusion Criteria:

1. Men and women aged 18-65 years
2. Primary diagnosis of obsessive compulsive disorder (OCD)
3. Yale Brown Obsessive Compulsive Scale (Y-BOCS) 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 (greater than 2x the upper limit of normal)