DIFFERENTIATING POSTTRAUMATIC-STRESS-DISORDER (PTSD) FROM MAJOR DEPRESSION (MDD) AND GENERALIZED ANXIETY DISORDER (GAD)

Questions about the differential diagnosis of Post-Traumatic Stress Di sorder (PTSD) have been raised since this category was reformulated in USM-III (APA, 1980). Clinicians have reported difficulties distinguis hing PTSD from other categories, particularly from Major Depressive an d Generalized Anxiety Disorders (MDD and GAD). Diagnostic validity can be established in several ways (e.g., through clinical descriptive st udies, laboratory experiments, Family history studies, etc.). In this paper, we describe one approach to validation thus far not applied to PTSD: This approach centers directly on whether clinicians can disting uish PTSD from,ther diagnostic categories. Experienced clinicians were asked to rate the extent to which a common set of 90 symptom items ch aracterized PTSD, MDD, and GAD. Ratings were analyzed with multivariat e and univariate analyses of variance and covariance, multiple discrim inant function analysis, and factor analysis; moreover, characteristic s of raters were examined for possible influences. Results indicated t hat clinicians readily distinguish PTSD from MDD and GAD as well as MD D from GAD. Findings are presented in terms of univariate analyses, 34 best discriminating items, and factors specifying dimensions differen tiating the syndromes of PTSD, MDD, and GAD. Rater characteristics did not influence diagnostic accuracy although significant differences in magnitude of symptom intensity were found. (C) 1997 Elsevier Science Ltd.