Treatment Outcomes for Co-Occurring Borderline Personality Disorder and Substance Use Disorders: A Systematic Review.

Objective: Almost half of patients diagnosed with borderline personality disorder (BPD) have a co-occurring substance use disorder (SUD). Patients with co-occurring BPD and SUD have poorer treatment outcomes, including lower rates of BPD remission and higher rates of substance-related harms. This systematic review aimed to evaluate existing treatments for co-occurring BPD and SUD. Methods: A systematic search was conducted using PsycINFO, Medline, PubMed, and Embase from inception to December 5, 2023. Selected studies assessed psychological or pharmacological interventions for patients with co-occurring BPD and SUDs. The impact of treatment on SUD and BPD symptoms was assessed. As an exploratory outcome, we examined the effects of interventions on emotion regulation. Results: Seventeen studies met our eligibility criteria. The most commonly studied intervention was dialectical behavior therapy (DBT; k = 9); most other interventions were evaluated by single studies. Treatment with DBT reduced SUD symptoms in some but not all studies. Overall, three psychotherapy studies assessed emotion regulation and found improvements following treatment. There were few pharmacotherapy trials in patients with BPD and SUD. There is evidence from these studies to suggest that specific pharmacotherapies for SUDs reduce substance use in patients with concurrent BPD. Conclusions: There is evidence that DBT improves emotion regulation for patients with co-occurring BPD and SUDs and some evidence that it reduces substance use. Future studies should systematically assess both BPD and SUD outcomes using larger samples and evaluate integrated treatments for BPD and SUDs.