Moderators of PTSD symptom change in group cognitive behavioral therapy and group present centered therapy.

To examine moderators of change during group-based intervention for Posttraumatic Stress Disorder (PTSD), multilevel models were used to assess trajectories of symptom clusters in male veterans receiving trauma focused Group Cognitive Behavioral Treatment (gCBT; N = 84) or non-trauma focused Group Present Centered Therapy (gPCT; N = 91; Sloan et al., 2018). Separate models were conducted for symptom clusters in each intervention, examining pre-treatment PTSD symptoms, pre-treatment depression severity, age, index trauma, and outcome expectancies as potential moderators. Unconditioned growth models for both gCBT and gPCT showed reductions in intrusions, avoidance, negative cognitions/mood, and arousal/reactivity (all p < .001). Distinct moderators of recovery emerged for each treatment. Reductions in avoidance during gCBT were strongest at high levels of pre-treatment PTSD symptoms (low PTSD: p =  .964, d = .05; high PTSD: p < .001, d = 1.31) whereas positive outcome expectancies enhanced reductions in cognitions/mood (low Expectancy: p =  .120, d = .50; high Expectancy: p < .001, d = 1.13). For gPCT, high levels of pre-treatment depression symptoms negatively impacted change in both intrusion (low depression: p < .001, d = .96; high depression: p =  .376, d = .22) and arousal/reactivity (low depression: p < .001, d = .95; high depression: p =  .092, d = .39) symptoms. Results support the importance of examining trajectories of change and their moderators for specific treatments, particularly when contrasting trauma focused and non-trauma focused treatments.