Abstract
IMPORTANCE: Body-focused repetitive behaviors (BFRBs; eg, skin picking) encompass a set of conditions at the interface of dermatology and psychiatry/psychology. The disorder is prevalent but currently underdiagnosed and undertreated. OBJECTIVE: To compare a new self-help intervention, habit replacement, against a wait-list control condition for the treatment of BFRBs. DESIGN, SETTING, AND PARTICIPANTS: This randomized clinical trial was conducted online in 2022. Participants were a population-based nonclinical sample with BFRBs and were recruited via social media. Initially, 481 individuals entered the assessment; 213 were excluded blind to results. A final sample of 268 participants were randomized. The intervention period was 6 weeks. INTERVENTIONS: Participants were randomized to a self-help intervention, habit replacement, or a wait-list control condition (each n = 134). MAIN OUTCOMES AND MEASURES: The Generic BFRB Scale-45 (GBS-45, self-report) represented the primary outcome. RESULTS: Individuals in the 2 conditions (n = 268; 241 [89.9%] women; mean [SD] age, 36.8 [11.1] years; skin picking, 68.3%; trichotillomania, 28.4%; nail biting, 36.6%; lip-cheek biting, 26.1%; other, 20.1%) did not differ on any baseline characteristics. The experimental group significantly improved on the primary outcome (GBS-45) for both the per-protocol (technique was used at least once weekly, ηp2 = 0.068, P = .001) and the intention-to-treat analyses relative to the wait-list control group (expectation-maximization algorithm; ηp2 = 0.019, P = .02). The interaction of group and time yielded statistical trends in favor of the experimental condition only on the Patient Health Questionnaire-9 and quality of life. For the Clinical Global Impressions scale, more individuals in the habit replacement group reported improvement (52.8% vs 19.6%; P < .001). User satisfaction in the habit replacement group was high. Moderation analyses that included all baseline variables showed that those who exhibited nail biting particularly benefited from the new technique. CONCLUSIONS AND RELEVANCE: The present proof-of-concept randomized clinical trial tentatively demonstrates that habit replacement is a feasible and effective self-help strategy against BFRBs, especially for nail biting. Study limitations include the lack of external assessment and verified diagnoses. In addition, the study is missing follow-up data. Self-help habit replacement shows promise in reducing BFRBs but not concomitant symptoms. TRIAL REGISTRATION: German Clinical Trials Register Identifier: DRKS00030511.