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NCT Number: NCT04899687

Study of Dextromethorphan in OCD and Related Disorders

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.

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Key information

Conditions

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

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Stanford University

Stanford, California, 94304, United States

Location status: Recruiting

Location contact

Alessa Gaeta, BA

CONTACT

[email protected]

650-723-4095

Peter van Roessel, MD, PhD

PRINCIPAL_INVESTIGATOR

About this study

Obsessive compulsive disorder (OCD) and the related disorders body dysmorphic disorder (BDD), somatic symptom disorder (SSD) and illness anxiety disorder (IAD) are psychiatric conditions characterized by recurrent, intrusive thoughts, feelings or images (obsessions or preoccupations) and repetitive or ritualized behaviors or avoidance performed to relieve obsession or preoccupation-related anxiety. They are a significant cause of mental health-related disability, and are inadequately served by available treatments.

This study tests whether an over-the-counter cough suppressant medicine, dextromethorphan, may offer symptom relief when combined with a low dose of fluoxetine, a standard prescription treatment for OCD and related disorders.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Fluoxetine

Drug

Fluoxetine 20mg (or previously prescribed dose) will be taken once daily by mouth for 8 weeks

Other names: Prozac

dextromethorphan

Drug

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 outcomes

  1. 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.

Secondary outcomes

  1. Improvement in clinical insight as measured by the BABS

    Time frame: Change from baseline will be assessed at 4 weeks and at 8 weeks.

    Improvement in clinical insight is measured by the Brown Assessment of Beliefs Scale (BABS), a scale assessing multiple dimensions of clinical insight as relevant to OCD and related disorders. The BABS rates multiple dimensions of clinical insight related to an identified belief. BABS scores range from 0-24, with higher scores indicating greater insight impairment. Response will be defined as a 35% reduction in BABS score.

Study contacts

Contact information is provided by the study sponsor or research team.

Alessa Gaeta, BA

CONTACT

[email protected]

650 497 2578

Sponsors and collaborators

Lead sponsor

Stanford University

Other

Collaborators

  • Avy L. & Roberta L. Miller Foundation

Registry information

Official study title

Fluoxetine/Dextromethorphan in Obsessive-Compulsive and Related Disorders: an Open-Label Crossover Pilot Study

Important dates

Study start
2022
Primary completion
2027
Study completion
2028
First posted
May 24, 2021
Registry last updated
May 20, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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