Emotional Dysregulation as a Mediator Between Childhood Adversity and Negative Urgency in Borderline Personality Disorder

BACKGROUND: The biosocial theory of borderline personality disorder (BPD) posits that emotional dysregulation develops from the transaction between a biological vulnerability and an invalidating environment (e.g., childhood adversity), and in turn leads to behavioral dyscontrol. This study aimed to empirically test this core mechanistic pathway in a non-Western clinical sample. METHODS: We hypothesized that the relationship between childhood adversity and the hallmark BPD trait of negative urgency (acting impulsively when distressed) would be mediated by difficulties in emotion regulation. A cross-sectional study was conducted with 45 adult patients with a Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) diagnosis of BPD in Hyderabad, India. Participants completed the Childhood Experience of Care and Abuse Questionnaire (CECA-Q), the Difficulties in Emotion Regulation Scale-Short Form (DERS-SF), and the Short UPPS-P (urgency, premeditation, perseverance, sensation seeking, and positive urgency) Impulsive Behaviour Scale. A bootstrapping-based mediation analysis (Hayes' PROCESS Model 4) was used to test the hypothesized indirect effect. RESULTS: The analysis revealed a significant indirect effect of childhood adversity on negative urgency through emotional dysregulation (Indirect Effect = 0.31, 95% bootstrapped CI: 0.14, 0.52). The direct effect of childhood adversity on negative urgency, which was significant in the initial correlation, became non-significant (B = 0.08, p = 0.450) after accounting for the mediator. This pattern is consistent with full mediation. CONCLUSION: This study provides strong, mechanism-based support for the biosocial model of BPD in an under-researched Indian context. The findings demonstrate that the pathogenic impact of childhood adversity on emotion-based impulsivity is explained by its disruption of emotion regulation capacities. This offers a clear empirical rationale for prioritizing emotion regulation-focused psychotherapies, such as dialectical behavior therapy, as the primary treatment approach for BPD.