Changes in post-traumatic stress disorder symptoms during residential treatment for borderline personality disorder: a longitudinal cross-lagged study.

BACKGROUND: Symptoms of borderline personality disorder (BPD) and post-traumatic stress disorder (PTSD) commonly co-occur. Recent evidence supports the concomitant treatment of BPD and PTSD. METHODS: This study uses a longitudinal cross-lagged panel model to examine BPD and PTSD symptom response in a sample of 110 women undergoing residential treatment for BPD. The naturalistic treatment primarily followed a dialectical-behavior therapy protocol, with individualized integration of other major evidence-based treatments (EBTs) for BPD, including mentalization-based treatment, good psychiatric management, and transference-focused psychotherapy. RESULTS: A residentially-based integration of treatment approaches resulted in significant reductions in BPD (d = 0.71) and PTSD (d = 0.75) symptoms. Moreover, changes in BPD symptoms prospectively predicted changes in PTSD symptoms (constrained path b = 1.73), but the reverse was not true (constrained path b = 0.05). CONCLUSIONS: A naturalistic integration of EBTs for BPD may benefit both BPD and PTSD symptoms even in the absence of PTSD-oriented intervention. Additionally, the attenuation of BPD symptoms may have positive impact on PTSD symptoms.