A comparison of four PTSD measures' convergent validities in Vietnam veterans.

We compared the convergent validities of four commonly used post-traumatic stress disorder (PTSD) measures in 80 help-seeking Vietnam veterans by contrasting their intercorrelations. When scored as continuous severity or frequency measures, the Mississippi Scale for Combat-related PTSD's and the Post-Traumatic Stress Disorder Interview's (PTSD-I's) concordances with other measures were similar to one anothers' and generally larger than those of either the Diagnostic Interview Schedule (DIS) PTSD module or the MMPI PTSD scale. However, when used only to identify stress disorder's presence or absence, the four techniques' concordances were nearly identical. This suggested that the four measures have similar convergent validities when used simply to identify PTSD, but that the PTSD-I and Mississippi scale offer better convergent validity than the MMPI or DIS instruments when used as severity measures.