Emotion Dysregulation as a Core Feature of Borderline Personality Disorder: Associations with Impulsivity and Symptom Severity in Emerging Adulthood

Objectives: This study aimed to explore the relationship between emotion dysregulation (ED), impulsivity, and symptom severity in emerging adults (16–25 years) diagnosed with Borderline Personality Disorder (BPD). Specifically, it sought to determine which ED dimensions differentiate BPD from non-clinical, independently of anxiety and depression, and how these relate to clinical features of BPD. Methods: A total of 184 participants (BPD = 44, non-clinical group = 140) completed standardized assessments, including the DERS (ED), UPPS-P (impulsivity), DIB-R (BPD), BDI-II (depression), and STAI-T (trait anxiety). Analyses included Mann–Whitney tests, quantile and logistic regressions, and Spearman correlations, adjusting for clinical covariates. Results: BPD participants scored significantly higher on all DERS subscales (p < 0.001). Adjusted regressions identified Impulse, Awareness, and Clarity as key discriminators (ORs: 5.91, 3.56, 2.90), and a total DERS score >129 increased BPD likelihood twelvefold. ED dimensions were associated with DIB-R symptom severity, especially Impulse and Strategies. Only Clarity showed a negative correlation with suicide attempts, suggesting greater emotional confusion was linked to fewer reported attempts. ED also correlated with urgency traits on the UPPS-P. Conclusions: ED—particularly emotional impulsivity, poor awareness, and low clarity—emerges as a core marker of BPD in emerging adulthood. These findings underscore the importance of early intervention strategies targeting emotional identification, modulation, and impulsivity control to mitigate clinical severity and long-term risk.