Predictors of change in cognitive processing therapy for veterans in a residential PTSD treatment program.

OBJECTIVE: Cognitive processing therapy is an evidence-based treatment for posttraumatic stress disorder (PTSD); however, questions remain regarding variability in treatment response.

METHOD: A total of 123 veterans participated in group-based cognitive processing therapy (CPT) in residential PTSD treatment. Change over time in PTSD symptoms was modeled as a function of selected demographic and clinical variables.

RESULTS: PTSD checklist (PCL) scores decreased by an average of 1 point per session (standard deviation [SD] = 0.1). Initial PCL scores were predicted by the Beck Depression Inventory-II (γ01 = 0.25; standard error [SE] = 0.08), Insomnia Severity Index (γ02 = 0.53; SE = 0.15), and Infrequency (F) scale of the Minnesota Multiphasic Personality Inventory-2 (γ03 = 0.09; SE = 0.04). Rate of change was predicted by the Somatic Complaints (RC1) scale (γ11 = -0.03; SE = 0.01) and the Antisocial Behavior (RC4) scale (γ12 = 0.02; SE = 0.01).

CONCLUSIONS: These results provide insight into characteristics that may influence degree of benefit received from group-based CPT.