Internalizing and externalizing personality styles and psychopathology in OEF-OIF veterans.

Previous research with other trauma populations demonstrated that internalizing and externalizing personality styles are associated with different PTSD comorbidities. The present study tested this association in two distinct Operation Enduring Freedom-Operation Iraqi Freedom (OEF/OIF) combat samples. Cluster analysis was used to categorize subtypes, which were compared on measures of PTSD, depression, anxiety, and substance use. Internalizers showed the highest rates of PTSD and depression. Externalizers had higher rates of alcohol problems in one sample only, whereas the other sample showed more substance misuse. In general, these findings suggest that this method of classifying trauma survivors is useful in OEF/OIF populations. Results suggest some differences across this population in terms of how substance use issues are expressed in externalizers.