Testing tolcapone for treating obsessive-compulsive disorder

A Double-Blind, Randomized, Placebo-Controlled Study of Tolcapone for OCD

PHASE2 · University of Chicago · NCT05624528

This study is testing if the medication tolcapone can help adults with moderate to severe obsessive-compulsive disorder feel better and improve their thinking skills compared to a placebo.

Quick facts

PhasePHASE2
Study typeInterventional
Enrollment85 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorUniversity of Chicago (other)
Locations1 site (Chicago, Illinois)
Trial IDNCT05624528 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to evaluate the efficacy and safety of tolcapone in adults suffering from moderate to severe obsessive-compulsive disorder (OCD). Participants will receive either tolcapone or a placebo for an 8-week period, with their symptoms assessed using the Yale Brown Obsessive Compulsive Scale (YBOCS). Additionally, the study will investigate the cognitive effects of tolcapone through neuropsychological tasks and explore the relationship between genetic factors and treatment outcomes. The goal is to determine if tolcapone can improve OCD symptoms and cognitive functions compared to placebo.

Who should consider this trial

Good fit: Ideal candidates for this study are adults aged 18-65 with a primary diagnosis of OCD and a YBOCS score of at least 21.

Not a fit: Patients with unstable medical conditions, current pregnancy, or a history of psychosis or bipolar disorder may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new therapeutic option for patients with OCD who do not respond adequately to current first-line treatments.

How similar studies have performed: While there is limited data on tolcapone specifically for OCD, previous studies have shown promise in using similar dopaminergic agents for cognitive and symptomatic improvements in related conditions.

Eligibility criteria

Show full inclusion / exclusion criteria
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

Where this trial is running

Chicago, Illinois

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Obsessive-Compulsive Disorder, OCD

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.