Developing Effective Response Inhibition Training for Symptom Relief in OCD and Trichotillomania

Developing Effective Response Inhibition Training for Symptom Relief in Obsessive-Compulsive and Related Disorders and Trichotillomania

Obsessive-compulsive disorder (OCD) and its related disorders (e.g., trichotillomania) are characterized by the marked difficulty in inhibiting unwanted or inappropriate responses. There is compelling evidence that poor response inhibition is a core cognitive feature of OCD and its related disorders, but no effective intervention exists that directly attempts to address this problematic cognitive deficiency. This study will examine the feasibility and clinical utility of a computerized cognitive training program designed to improve response inhibition among individuals diagnosed with OCD or trichotillomania.This training program offers systematic practice of response inhibition in the form of a 40-level computer game. Individuals with these conditions will be randomized to either 8 sessions of (a) computerized response inhibition training (RIT) or (b) placebo computer training (PLT). We hypothesize that RIT will outperform PLT in improving response inhibition capabilities and reducing relevant clinical symptoms. In sum, this project is expected to generate important knowledge to guide the development of effective computer-based treatment approaches that may help reduce critical problems of existing treatments such as suboptimal patient retention and treatment under-utilization, thereby improving overall treatment response rates among individuals suffering from OCD and related conditions.

This is a computerized video game that offers 40 training levels, which aims to enhance the individual's response inhibition performance

This placebo control training looks very similar to the response inhibition training program in its appearance. However, it does not offer any practice related to response inhibition capabilities.

Composite Score of Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and National Institute of Mental Health (NIMH)

This is a clinician-administered rating scale of OCD symptom severity, most widely used in treatment outcome research for OCD, and a clinician-administered rating scale of hair pulling symptoms, widely used in clinical trial research for trichotillomania. Given the inclusion of two different diagnostic conditions, the primary outcome for the current study is the z score of the symptom rating severity obtained from the two rating scales, with higher values indicating greater symptom severity.

Stop Signal Reaction Time (SSRT; time taken to complete the inhibitory process) is estimated using the tracking algorithm on the computerized stop-signal task, which adjusts the stop signal delay automatically (by 50ms) to maintain the rate of successful inhibition on stop-signal trials at 50%.

The Clinical Global Impression Severity and Improvement (CGI) is a clinician-administered rating scale widely used to assess the overall severity of the target condition in treatment outcome research. The CGI is assessed on a 7-point scale, with the severity scale from 1 (Normal, not at all ill) through to 7 (Among the most severely ill patients). Thus, the higher CGI severity rating score indicate a greater level of overall illness.

The number of commission errors on the go/no-go task is a commonly used measure of response inhibition. In this task, participants are asked to withhold their responses on no-go trials. If they fail to withhold their response in a no-go trial (i.e., pressing the response key to the no-go signal), this response counts toward the total number of commission errors. Therefore, a greater number of commission errors on this task reflects a greater level of inhibitory control deficit.

Inclusion Criteria: Principal diagnosis of obsessive-compulsive disorder or trichotillomania Exclusion Criteria: Current substance use problems Current/Past Psychotic disorder, bipolar disorder, or schizophrenia Attention deficit/hyperactivity disorder or tic disorder Severe depressive symptoms Current psychotherapy Current suicidality Estimated intellectual functioning < 80 Lack of response inhibition deficits on a stop-signal task