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Study of Dextromethorphan in OCD and Related Disorders

This study is exploring if combining dextromethorphan, an over-the-counter cough medicine, with fluoxetine (a standard treatment for OCD) can help reduce symptoms of Obsessive-Compulsive Disorder (OCD) and related conditions like Body Dysmorphic Disorder (BDD), Illness Anxiety Disorder (IAD), and Somatic Symptom Disorder (SSD). Researchers will give participants fluoxetine daily for eight weeks and dextromethorphan twice daily for four weeks, with the dextromethorphan dose increasing weekly. The study aims to see if this combination improves symptoms, measured by changes in a standard symptom scale (Y-BOCS) at 4 and 8 weeks. You may be able to join if you are 18-65 years old, live in California, and have one of these diagnoses. The current status of this study is unclear.

Study design
This is an interventional study planning to enroll 60 participants. It tests two drugs: fluoxetine and dextromethorphan.
What's involved
You would take fluoxetine daily for 8 weeks and dextromethorphan twice daily for 4 weeks. Symptom improvement will be assessed at 4 and 8 weeks.
Compensation
Not stated in the trial record.
Follow-up
Your symptoms will be assessed at 4 weeks and at 8 weeks after starting the study.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT04899687

Study of Dextromethorphan in OCD and Related Disorders

Recruiting
PHASE2Ages 18–65InterventionalTreatment
Stanford University
~60 participants
Updated 2026-05-20 on ClinicalTrials.gov
What's tested:FluoxetineDextromethorphan

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Improvement in OCD or related disorder symptoms as measured by the Y-BOCS
Measured over Change from baseline will be assessed at 4 weeks and at 8 weeks.

Conditions

Obsessive-Compulsive Disorder
Illness Anxiety Disorder
Body Dysmorphic Disorders
Somatic Symptom Disorder

Explore related trials

Bodily distress disorderBody dysmorphic disorderIllness anxiety disorderObsessive Compulsive Disorder

Where it's being run

1 sites across 1 states
California1

Study leadership

  • Peter J van Roessel, MD PhD · PRINCIPAL_INVESTIGATOR · Stanford University

Who to contact

Alessa Gaeta, BA
[email protected]
650 497 2578
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

Diagnosis of obsessive-compulsive disorder (OCD), body dysmorphic disorder (BDD), illness anxiety disorder (IAD) or somatic symptom disorder (SSD)
Living within California
Capacity to provide informed consent

Exclusion

Current bipolar disorder or psychotic disorder
Active moderate or severe substance use disorder, lifetime severe substance use disorder
Pregnant or nursing women
Use of prescribed psychotropic medications other than fluoxetine for 2 weeks prior to study start
Having commenced OCD-targeted exposure and response-prevention (ExRP) psychotherapy within 2 months of study start

What this trial measures

  • Improvement in OCD or related disorder symptoms as measured by the Y-BOCSChange from baseline will be assessed at 4 weeks and at 8 weeks.

    Improvement in OCD severity is measured by the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), a gold standard measure of the severity of obsessions and compulsions. Variants of the Y-BOCS designed for assessment of body dysmorphic disorder or illness anxiety disorder/somatic symptom disorder will be used as appropriate. Y-BOCS scores range from 0 to 40, with higher scores indicating greater severity of symptoms. Response will be defined as a 35% reduction in Y-BOCS score.