Personality assessment inventory internalizing and externalizing structure in veterans with posttraumatic stress disorder: associations with aggression.

Posttraumatic stress disorder (PTSD) is associated with aggressive behavior in veterans, and difficulty controlling aggressive urges has been identified as a primary postdeployment readjustment concern. Yet only a fraction of veterans with PTSD commit violent acts. The goals of this study were to (1) examine the higher-order factor structure of Personality Assessment Inventory (PAI) scales in a sample of U.S. military veterans seeking treatment for PTSD; and (2) to evaluate the incremental validity of higher-order latent factors of the PAI over PTSD symptom severity in modeling aggression. The study sample included male U.S. Vietnam (n = 433) and Iraq/Afghanistan (n = 165) veterans who were seeking treatment for PTSD at an outpatient Veterans Affairs (VA) clinic. Measures included the Clinician Administered PTSD Scale, the PAI, and the Conflict Tactics Scale. The sample was randomly split into two equal subsamples (n's = 299) to allow for cross-validation of statistically derived factors. Parallel analysis, variable clustering analysis, and confirmatory factor analyses were used to evaluate the factor structure, and regression was used to examine the association of factor scores with self-reports of aggression over the past year. Three factors were identified: internalizing, externalizing, and substance abuse. Externalizing explained unique variance in aggression beyond PTSD symptom severity and demographic factors, while internalizing and substance abuse did not. Service era was unrelated to reports of aggression. The constructs of internalizing versus externalizing dimensions of PTSD may have utility in identifying characteristics of combat veterans in the greatest need of treatment to help manage aggressive urges. Published 2014 Wiley Periodicals, Inc.