Transcranial Direct Current Stimulation Augmented Exposure and Response Prevention for Obsessive-Compulsive Disorder

Study Overview
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Brief Summary
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This study is investigating whether combining noninvasive brain stimulation with behavior therapy can help to improve outcomes for obsessive-compulsive disorder (OCD). Exposure and response prevention (ERP) -- a specific type of behavior therapy -- is a first line treatment for OCD. This study will test whether a form of noninvasive brain stimulation called transcranial direct current stimulation (tDCS), can help ERP work better.

Official Title
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tDCS for Inhibitory Control Deficits: A Test in OCD

Conditions
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Obsessive-Compulsive Disorder

Intervention / Treatment
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* Other: ERP plus tDCS
* Other: ERP plus sham tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Current primary OCD diagnosis and current Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) total score of ≥16 18-65 years of age Ability to speak, read, write, and understand English sufficiently well to complete study procedures and provide informed consent Right-handed No use of psychiatric medications or stable psychiatric medication use for a minimum of 6 week prior to study entry. Psychiatric medications will be limited to the following: serotonin reuptake inhibitors (SRI; including clomipramine), combination antidepressants (including bupropion and serotonin-norepinephrine reuptake inhibitors), buspirone, benzodiazepines, and/or stimulants Naive to tDCS Exclusion Criteria: Active substance use disorder Lifetime diagnosis of psychotic or bipolar mood disorder Previous minimally adequate trial of ERP (e.g., at least 16 sessions including both therapist and self-directed exposure and response prevention) Therapy outside the study protocol which has evidence for efficacy with OCD during the study intervention period Active suicidal or homicidal ideation Organic brain disease or injury Any health problems that would interfere with study participation, including contraindications to tDCS (e.g., skin condition, mental implant in skull) Women who are pregnant or breastfeeding. All women participants of child-bearing age are required to have a negative pregnancy test prior to treatment, and must use medically acceptable birth control during study participation. Medically acceptable birth control includes: established oral, injected, implanted, or vaginal ring hormonal contraception, an intrauterine device (IUD), two barrier contraception methods (condom or occlusive cap with spermicidal foam/gel/film/cream/suppository), or having a vasectomized partner Use of anticonvulsant medications (including depakote, gabapentin, tegretol, dilantin, lamictal) and/or glutamate-acting agents (including n-acetylcysteine, riluzole, amantadine, memantine).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ERP plus tDCS<br>ERP plus anodal tDCS of right inferior frontal gyrus | Other: ERP plus tDCS<br>* Participants in the ERP plus tDCS arm will receive an 11-session program, including 10 sessions which include both tDCS and ERP. During these sessions, 20 minutes of anodal tDCS will be delivered over right inferior frontal gyrus prior to the ERP exercise.<br>|
| Active Comparator: ERP plus sham tDCS<br>ERP plus sham tDCS of right inferior frontal gyrus | Other: ERP plus sham tDCS<br>* Participants in the ERP plus sham tDCS arm will receive an 11-session program, including 10 sessions which include both sham tDCS and ERP. During these sessions, 20 minutes of sham tDCS will be delivered over right inferior frontal gyrus prior to the ERP exercise.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Yale-Brown Obsessive Compulsive Scale (Y-BOCS): Total Score | The Y-BOCS is a well-known measure for assessing OCD symptom severity. Total scores can range from 0-40, with higher scores corresponding to greater severity of symptoms. | Post-treatment (approximately 6.5 weeks post-baseline) | 
| Client Satisfaction Questionnaire-8: Total Score | The Client Satisfaction Questionnaire-8 is measure of client satisfaction. Scores can range from 8-32, with higher scores corresponding to greater satisfaction. | Post-treatment (approximately 6.5 weeks post-baseline) | 
| Rates of Session Completion | Average number of intervention sessions completed | Approximately 6.5 weeks post-baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Yale-Brown Obsessive-Compulsive Scale: Total Score | The Y-BOCS is a well-known measure for assessing OCD symptom severity. Total scores can range from 0-40, with higher scores corresponding to greater severity of symptoms. | 1-month follow up (Approximately 11 weeks after baseline assessment) | 
| Client Satisfaction Questionnaire-8: Total Score | The Client Satisfaction Questionnaire-8 is measure of client satisfaction. Scores can range from 8-32, with higher scores corresponding to greater satisfaction. | 1-month follow up (Approximately 11 weeks after baseline assessment) | 
| Rates of Retention in Intervention | Number of randomized participants who remained in the intervention phase of the study and completed all intervention sessions. | Approximately 6.5 weeks post-baseline |