Relationship Between Borderline Personality Pathology and Problematic Alcohol Use in Patients With Mood Disorders

Objective It remains unclear whether specific borderline personality pathology (BPP) traits differentially relate to problematic alcohol use (PAU) across mood disorder diagnoses. This study examined diagnosis-specific patterns of association between BPP and PAU in major depressive disorder (MDD), bipolar I disorder (BD I), bipolar II disorder (BD II), and non-clinical participants (NCP).Methods Participants (n=3,807; NCP=3,000, MDD=311, BD I=126, BD II=370) completed Personality Assessment Inventory–Borderline Personality Disorder and Alcohol Use Disorders Identification Test. Partial correlation analyses, multivariable linear regression analyses, and interaction analyses were conducted to examine the associations, adjusting for demographic factors and current mood symptoms.Results BPP was significantly associated with PAU across the total sample, particularly stronger for dependence symptoms and harmful alcohol use than for hazardous alcohol use. At the trait level, affective instability and self-harm were the BPP components most consistently associated with PAU outcomes. Diagnosis-specific patterns were observed. Self-harm was the primary predictor in BD II, while affective instability predominated in MDD, whereas in NCP both traits contributed. No significant associations were found in BD I. Interaction analyses revealed that BPP’s impact on hazardous alcohol use was significantly amplified in BD II compared to NCP.Conclusion BPP-PAU associations varied by diagnosis driven by distinct affective–impulsive mechanisms. Screening BPP traits in BD II may help identify individuals at elevated risk for hazardous drinking.