This study sought to identify specific trajectories of posttraumatic stress disorder (PTSD) and depression symptom change (and the relationship thereof) within a variable length course of cognitive processing therapy (CPT). Clinical characteristics, including initial severity of PTSD and depressive symptoms and characterological features consistent with personality disorder diagnoses, were examined as potential predictors of treatment response trajectory. Male and female interpersonal violence survivors (N = 69) with PTSD were treated with a modified form of CPT wherein treatment end was dictated by individual course of recovery (4–18 sessions). Latent class growth analysis and Bayesian information criteria revealed three distinct groups based on change patterns (partial responders, consistent responders, and initial responders). Baseline PTSD and depressive symptoms and characterological features were associated with patterns of change. Findings provide evidence for variability in efficiency of response to PTSD treatment and highlight the need for continued assessment of progress to inform the course of therapy.
