NCT04899687 · Stanford University
Study of Dextromethorphan in OCD and Related Disorders
What this study is about
The purpose of the study is to assess the tolerability and effectiveness of dextromethorphan in combination with fluoxetine for symptom relief in OCD and related disorders.
View original scientific description
The purpose of the study is to assess the tolerability and efficacy of dextromethorphan in combination with fluoxetine for symptom relief in OCD and related disorders.
Interventions
DRUG
Fluoxetine
Fluoxetine 20mg (or previously prescribed dose) will be taken once daily by mouth for 8 weeks
DRUG
Dextromethorphan
Dextromethorphan, an over-the-counter cough suppressant, will be taken by mouth twice daily for four weeks of the study, starting at 15mg per dose, and increasing weekly as tolerated to a maximum of 60mg per dose.
Primary outcome measures
Improvement in OCD or related disorder symptoms as measured by the Y-BOCS
Time frame: Change 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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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 criteria
- 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
Where
- Stanford, California
Collaborators
Avy L. & Roberta L. Miller Foundation
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 20, 2026 · Source of record for eligibility and locations