Examining posttraumatic stress disorder as a predictor of treatment response to dialectical behavior therapy.

Objective This study examined the presence of posttraumatic stress disorder (PTSD) as a predictor of treatment response to dialectical behavior therapy (DBT) across the primary outcomes of interest within DBT (i.e., borderline personality disorder [BPD] symptoms, deliberate self-harm, emotion regulation [ER] difficulties) and PTSD symptoms. Method Participants (N = 56) were consecutive admissions to an outpatient DBT clinic that completed diagnostic interviews at intake and self-report outcome measures at intake and every 3 months throughout the treatment. Results Patients with (vs. without) a PTSD diagnosis did not report greater clinical severity at intake on most outcome measures, with the exception of PTSD symptom severity and, among older patients only, ER difficulties. The presence of a PTSD diagnosis was not associated with poorer treatment response to DBT. Instead, PTSD was associated with better response on the measure of BPD symptom severity. Conclusions The results suggest that patients with PTSD can benefit from DBT.