Personality traits as predictors of PTSD and depression symptoms following exposure-based treatment in an intensive outpatient program.

We aimed to assess the associations between pre-treatment personality traits on symptoms of posttraumatic stress disorder (PTSD) and depression before and after an intensive outpatient treatment program (IOP). In a secondary data analysis of a sample of  = 665 veteran or active-duty U.S. military servicemembers who completed IOP treatment (65.7 % male; mean age = 41.8; 57.0 % White), we used multiple regression analyses and latent change score models to investigate pre-treatment measures of Five Factor Model traits, psychopathy, and narcissism as predictors of PTSD and depression symptoms across timepoints (i.e., from pre-treatment up to 12-months post-treatment) following completion of exposure-based, cognitive-behavioral IOP treatment. Neuroticism and Extraversion were positively and negatively, respectively, associated with PTSD and depression symptoms at all timepoints, and facets from other domains (e.g., trust, self-efficacy) also bore medium-to-large associations with these symptoms at each timepoint. Psychopathy and narcissism bore null-to-small relations with psychopathology. Pre-treatment PTSD and depression symptoms were consistent predictors of post-treatment symptoms, as well as of greater symptom reduction from pre- to post-treatment, pre-treatment to 12-month follow-up, and post-treatment to 12-month follow up. Higher Extraversion was significantly related to greater change in PTSD and depression symptoms from pre- to post-treatment. No other personality traits were related to symptom change beyond pre-treatment symptoms on any timescale. Personality traits have large associations with PTSD and depression symptoms over time, but the degree to which they account for IOP treatment response beyond baseline symptoms is relatively small.