Social Anxiety Symptoms and Body-Focused Repetitive Behaviour Severity in Adolescents: A Serial Mediation Analysis of Shame and Emotion Regulation Difficulties.

Abstract

Body-focused repetitive behaviour disorders (BFRBDs), including trichotillomania (TTM) and skin-picking disorder (SPD), typically emerge during adolescence. These disorders have been conceptualized within emotion regulation models, in which body-focused repetitive behaviours (BFRBs) may function as attempts to regulate aversive emotional states. Although anxiety frequently co-occurs with BFRBDs, its association with BFRB severity is generally modest, highlighting the need to examine affective and regulatory processes. This cross-sectional study examined the associations among social anxiety, shame-proneness, emotion regulation difficulties and BFRB severity using a serial mediation model. Participants were 107 adolescents aged 12-18 years (80.4% female) who met DSM-5 criteria for TTM or SPD and were recruited from a tertiary child and adolescent psychiatry clinic. Diagnoses were established using semi-structured clinical interviews. The analysis controlled for age and sex. Social anxiety was positively correlated with shame, emotion regulation difficulties and BFRB severity (r = 0.28-0.31, all p < 0.01). In the serial model, social anxiety was associated with greater shame, which was associated with greater emotion regulation difficulties; in turn, emotion regulation difficulties were associated with greater BFRB severity. The total indirect effect (B = 0.162, 95% CI [0.038, 0.337]) and the serial indirect effect through both mediators (B = 0.117, 95% CI [0.040, 0.257]) were significant, whereas neither single-mediator indirect effect was significant. The direct association remained significant (B = 0.302, p = 0.022), consistent with partial statistical mediation. These findings support the proposed theory-based model but do not establish temporal or causal ordering.