The role of personality traits and profiles in posttrauma comorbidity

Many service members experience symptoms of posttraumatic stress disorder (PTSD) after deployment. PTSD can vary widely in its presentation and associated features, such as comorbid conditions. Research has shown that veterans with PTSD and an internalizing personality profile are more likely to experience internalizing comorbidity (e.g., anxiety, depression), whereas veterans with PTSD and an externalizing personality profile are more likely to experience externalizing comorbidity (e.g., substance abuse, aggression). To date, however, this research has been limited by a focus on diagnosable disorders and personality categories. In a nonclinical sample of 224 National Guard/Reserve service members who had served since 2001, we explored whether personality traits (measured continuously) moderated associations of PTSD symptom severity with the severity of internalizing (depression, anxiety) and externalizing (alcohol abuse, aggression) symptoms. Results showed that the association of PTSD with anxiety was stronger when extraversion was lower (corresponding to an internalizing personality profile). Moreover, the association of PTSD with alcohol abuse was stronger when extraversion was high and conscientiousness was low (corresponding to an externalizing personality profile). Surprisingly, this association was also stronger when extraversion was low and conscientiousness was high. Results offer additional insights into prior research on personality and comorbidity.