Trajectories of complex posttraumatic stress disorder symptoms change in phase-based treatment, prolonged exposure, and skills-training.

International Classification of Diseases (11th ed.; ICD-11) Complex Posttraumatic Stress Disorder (CPTSD) is a new diagnostic category consisting of PTSD and disturbances of self-organization (DSO) symptoms. This study compares the trajectories of ICD-11 PTSD and DSO symptoms change in three treatments: a phase-based intervention, STAIR Narrative Therapy (SNT), Prolonged Exposure (PE), and skills-training in affect and interpersonal regulation (STAIR). Ninety-two adult patients with ICD-11 CPTSD following childhood abuse were randomly assigned to treatment conditions. Piecewise latent curve models of self-reported symptoms were used to compare the change trajectories. Piece 1 corresponds to phase 1 (SNT) and active treatment (PE/STAIR), and piece 2 corresponds to phase 2 (SNT) and the first two months after treatment (PE/STAIR). In piece 1, PTSD symptom decline was steeper in PE compared to skills-training yielding a difference of d = -0.66, 95% CI [-0.99, -0.32] compared to SNT, and d = -0.56, 95% CI [-0.90, -0.23] compared to STAIR. In piece 2, PTSD symptom decline accelerated in SNT compared to PE, d = -0.25, 95% CI [-0.05, -0.45], but not compared to STAIR. The rate of DSO symptoms decline did not differ among conditions during treatment but decelerated more in PE compared to STAIR after treatment, d = -0.30, 95% CI [-0.08, -0.51]. Trauma-focused interventions may be the preferable treatment approach for PTSD symptoms and comparable to skills-training in reducing DSO symptoms during treatment. Compared to trauma-focused interventions there may be a potential spillover effect of skills-training on DSO symptoms in daily life after treatment.