An Internet-Based Controlled Trial of Interpretation Bias Modification Versus Progressive Muscle Relaxation for Body Dysmorphic Disorder

Objective: The current study extended upon previous research efforts by evaluating the utility and feasibility of an 8-session Internet-based interpretation bias modification (IBM) training protocol targeting evaluation- and appearance-related threat biases characteristic of the disorder compared to a progressive muscle relaxation (PMR) condition for treatment of body dysmorphic disorder (BDD). Method: Fifty participants with BDD were recruited from across the United States and randomly assigned to eight sessions of either IBM or PMR. Assessments of interpretation bias, BDD symptoms, depression, and anxiety were administered at pretreatment, 1-week posttreatment, and 3-month follow-up. Results: Compared to the PMR group, individuals in the IBM condition reported less negative/threat interpretation biases and greater positive/benign interpretation biases at posttreatment and follow-up. There were no significant differences between groups with regard to BDD symptoms, depression, or anxiety. Clinically significant improvement was common in both conditions (IBM = 64.0%; PMR = 52.0%), though it did not differ between them. Conclusions: Contrary to our hypothesis, IBM did not outperform PMR with regard to BDD symptom reduction, though both treatments yielded significant improvements on symptom outcomes. Findings suggest that IBM and/or PMR may be promising treatment strategies for BDD, perhaps adjunctively. Overall, these findings provide helpful future directions for IBM research and provide an additional lens through which to examine its potential effectiveness for BDD.