Long-term effects of dialectical behaviour therapy for posttraumatic stress disorder and cognitive processing therapy 9 months after treatment termination.

The complexity of posttraumatic stress disorder (PTSD) symptoms related to childhood abuse (CA) present challenges for effective psychotherapeutic treatment. Consequently, there is great interest in the long-term effectiveness of psychological treatments for this population. This study aims to investigate the long-term outcomes of Dialectical Behaviour Therapy for PTSD (DBT-PTSD) and Cognitive Processing Therapy (CPT) 9 months after treatment termination. This is a long-term analysis from a randomised-controlled trial of DBT-PTSD versus CPT (registration number DRKS00005578). Initially, 193 individuals with CA-related PTSD were randomly allocated to receive either DBT-PTSD ( = 98) or CPT ( = 95). The primary outcome the Clinician-administered PTSD-Scale for DSM-5 (CAPS-5) was administred at baseline, treatment completion (15 months post-randomization) and at the 9-month follow-up. Secondary outcomes included self-reported PTSD severity (PCL-5), dissociation (DSS), severity of borderline symptoms (BSL-23), and psychosocial functioning (GAF). No significant changes were observed in the primary (CAPS) and all other outcomes from post-intervention to 9-months follow-up in both the DBT-PTSD (CAPS:  = 15.60, = 14.93) and CPT group (CAPS:  = 18.80,  = 17.41). Between-group analyses at 9-months follow-up were significantly in favour of DBT-PTSD compared to CPT with small to medium effect sizes on all outcomes ranging from = 0.35 on the CAPS to = 0.57 on the BSL-23 and GAF. Our results indicate that treatment effects of psychotherapy addressing complex presentations of PTSD persist 9 months after treatment termination. In addition, the superiority of DBT-PTSD as compared to CPT found at treatment termination, was confirmed at 9-months follow-up. German Clinical Trials Register identifier: DRKS00005578..