Study of Dextromethorphan in OCD and Related Disorders

Sponsor

Stanford University (Other)

Overall Status

Recruiting

CT.gov ID

NCT04899687

Collaborator

Avy L. & Roberta L. Miller Foundation (Other)

Enrollment

Location

Arms

42.3

Anticipated Duration (Months)

1.4

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Obsessive-Compulsive Disorder Illness Anxiety Disorder Body Dysmorphic Disorders Somatic Symptom Disorder	Drug: Fluoxetine Drug: Dextromethorphan	Phase 2

Detailed Description

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.

Study Design

Study Type:

Interventional

Anticipated Enrollment :

60 participants

Allocation:

Randomized

Intervention Model:

Crossover Assignment

Intervention Model Description:

After signing consent and baseline assessments, participants will be randomized 1:1 to Group A or Group B for the purposes of sequencing fluoxetine vs combined fluoxetine/dextromethorphan treatment periods.After signing consent and baseline assessments, participants will be randomized 1:1 to Group A or Group B for the purposes of sequencing fluoxetine vs combined fluoxetine/dextromethorphan treatment periods.

Masking:

Single (Outcomes Assessor)

Masking Description:

Symptom rating will be done by independent evaluators blind to treatment allocation.

Primary Purpose:

Treatment

Official Title:

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

Actual Study Start Date :

Jan 20, 2022

Anticipated Primary Completion Date :

Aug 1, 2023

Anticipated Study Completion Date :

Aug 1, 2025

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Group A: fluoxetine then fluoxetine plus dextromethorphan Group A participants will take fluoxetine 20mg (or prior dose) daily for 4 weeks, and will then continue fluoxetine while adding over the counter dextromethorphan, with doses increasing weekly as tolerated, for 4 weeks.	Drug: Fluoxetine Fluoxetine 20mg (or previously prescribed dose) will be taken once daily by mouth for 8 weeks Other Names: Prozac 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.
Experimental: Group B: fluoxetine plus dextromethorphan then fluoxetine Group B participants will take fluoxetine 20mg (or prior dose) daily together with over the counter dextromethorphan, with doses increasing weekly as tolerated, for 4 weeks, and then will stop dextromethorphan, continuing fluoxetine alone for 4 weeks.	Drug: Fluoxetine Fluoxetine 20mg (or previously prescribed dose) will be taken once daily by mouth for 8 weeks Other Names: Prozac 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.

Arm

Intervention/Treatment

Experimental: Group A: fluoxetine then fluoxetine plus dextromethorphan

Group A participants will take fluoxetine 20mg (or prior dose) daily for 4 weeks, and will then continue fluoxetine while adding over the counter dextromethorphan, with doses increasing weekly as tolerated, for 4 weeks.

Drug: Fluoxetine

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

Other Names:

Prozac

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.

Experimental: Group B: fluoxetine plus dextromethorphan then fluoxetine

Group B participants will take fluoxetine 20mg (or prior dose) daily together with over the counter dextromethorphan, with doses increasing weekly as tolerated, for 4 weeks, and then will stop dextromethorphan, continuing fluoxetine alone for 4 weeks.

Drug: Fluoxetine

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

Other Names:

Prozac

Drug: Dextromethorphan

Outcome Measures

Primary Outcome Measures

Improvement in OCD or related disorder symptoms as measured by the Y-BOCS [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 Outcome Measures

Improvement in clinical insight as measured by the BABS [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.

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 65 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

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