Personality traits and combat exposure as predictors of psychopathology over time.
BACKGROUND
Research suggests that personality traits have both direct and indirect effects on the development of psychological symptoms, with indirect effects mediated by stressful or traumatic events. This study models the direct influence of personality traits on residualized changes in internalizing and externalizing symptoms following a stressful and potentially traumatic deployment, as well as the indirect influence of personality on symptom levels mediated by combat exposure.


METHODS
We utilized structural equation modeling with a longitudinal prospective study of 522 US National Guard soldiers deployed to Iraq. Analyses were based on self-report measures of personality, combat exposure, and internalizing and externalizing symptoms.


RESULTS
Both pre-deployment Disconstraint and externalizing symptoms predicted combat exposure, which in turn predicted internalizing and externalizing symptoms. There was a significant indirect effect for pre-deployment externalizing symptoms on post-deployment externalizing via combat exposure (p < 0.01). Negative Emotionality and pre-deployment internalizing symptoms directly predicted post-deployment internalizing symptoms, but both were unrelated to combat exposure. No direct effects of personality on residualized changes in externalizing symptoms were found.


CONCLUSIONS
Baseline symptom dimensions had significant direct and indirect effects on post-deployment symptoms. Controlling for both pre-exposure personality and symptoms, combat experiences remained positively related to both internalizing and externalizing symptoms. Implications for diagnostic classification are discussed.
Center for Chronic Disease Outcomes Research,Minneapolis,MN,USA.
E
E
Koffel
Minneapolis VA Healthcare System,Minneapolis,MN,USA.
M D
MD
Kramer
Minneapolis VA Healthcare System,Minneapolis,MN,USA.
P A
PA
Arbisi
Center for Chronic Disease Outcomes Research,Minneapolis,MN,USA.
C R
CR
Erbes
Minneapolis VA Healthcare System,Minneapolis,MN,USA.
M
M
Kaler
Center for Chronic Disease Outcomes Research,Minneapolis,MN,USA.
M A
MA
Polusny
D000328:Adult; D003130:Combat Disorders / Q000503:physiopathology*; D003866:Depressive Disorder / Q000503:physiopathology*; D005260:Female; D006801:Humans; D054542:Iraq War, 2003-2011; D008297:Male; D008889:Military Personnel; D010551:Personality / Q000502:physiology*; D013313:Stress Disorders, Post-Traumatic / Q000503:physiopathology*; D019966:Substance-Related Disorders / Q000503:physiopathology*
Externalizing disorders; internalizing disorders; personality; personality traits and combat exposure as predictors of psychopathology over time; trauma