Abstract
BACKGROUND: Body dysmorphic disorder (BDD) is a severe, chronic disorder if untreated. Smartphone cognitive behavioral therapy (CBT) for BDD is efficacious and can reduce key treatment barriers (e.g., lack of clinicians, cost, stigma). While promising, little is known about who is more or less likely to benefit from this approach. METHODS: This is a secondary data analysis of a randomized, waitlist-controlled trial of smartphone CBT for BDD. Participants (N = 80) were recruited nationally and randomized to receive a 12-week, coach-guided CBT for BDD app, either immediately or after a 12-week waitlist. The main outcome for this analysis was BDD severity (BDD-YBOCS) over time (baseline, week 6, week 12) during the active app use phase in each randomized group (n = 74). Secondary outcomes included treatment response (≥30 % reduction in BDD-YBOCS) and remission (total BDD-YBOCS ≤16) at end-of-treatment. RESULTS: Immediate (vs. delayed) CBT predicted better outcomes (symptom improvement), as did gender identity (symptom improvement), higher baseline treatment credibility and expectancy (response, remission), lower baseline BDD severity (remission), and sexual minority status (vs. heterosexual; response, remission). LIMITATIONS: Limitations include the relatively small sample, drop-out rate of 22 %, and limited gender and racial-ethnic diversity. CONCLUSIONS: These results highlight a potential advantage of smartphone CBT in historically marginalized populations, and the importance of efforts to hasten treatment access, bolster confidence in the treatment at treatment onset, and develop stratified care models to optimize treatment allocation and efficacy.