BACKGROUND: Borderline personality disorder (BPD) and substance use disorder (SUD) frequently co-occur. Although some research has investigated the factors related to this comorbidity, few have isolated the effects of SUD on a BPD diagnosis.
METHODS: Patients presenting for treatment were assessed with the Structured Clinical Interview for DSM-IV, the BPD module of the Structured Interview for DSM-IV Personality, the Difficulties in Emotion Regulation Scale (DERS), and the Five Facet Mindfulness Questionnaire (FFMQ). Analyses were conducted to determine how individuals diagnosed with BPD differ from individuals diagnosed with BPD and SUD.
RESULTS: Among the BPD diagnostic criteria, patients with comorbid BPD and SUD endorsed impulsivity at higher rates, and patients with only BPD more frequently endorsed frantic efforts to avoid real or imagined abandonment. The 2 groups were not distinguished by scores on the DERS, although the comorbid group reported higher FFMQ scores, specifically on the acting with awareness subscale.
CONCLUSIONS: Borderline personality disorder is fundamentally based on emotion dysregulation. Substance use and efforts to avoid abandonment are both forms of maladaptive coping that stem from this dysregulation, and individuals with BPD may tend to rely on one or the other. Future studies should continue to evaluate these clinical features across diverse groups.