Examining comorbidity and posttraumatic stress disorder in a Vietnam veteran population using the MMPI-2

Examined the discriminant validity of the MMPI-2 in assessing comorbidity in a posttraumatic stress disorder (PTSD) Vietnam veteran population. The Structured Clinical Interview for the DSM-III-R (SCID) was used to diagnose veterans and to classify them into four groups: PTSD Only, PTSD with mood disorders, PTSD with other anxiety disorders, and PTSD with mood and anxiety disorders. All groups had clinical elevations on scales F, 1, 2, 3, 4, 6, 7, 8, 0, PK, and PS, with peak elevations on scales 8, 7, and 2. The PTSD Only group's MMPI-2 scores were not significantly lower than other groups' scores. The PTSD+Mood/Anxiety group was significantly more elevated on scales 2 and 7 than the PTSD Only and PTSD+Anxiety group but did not otherwise show significantly higher scale elevations than other groups. No significant differences existed between groups on scales F, L, K, PK, and PS. Implications of these results for PTSD and the current diagnostic system are explored.