Dimensionality of posttraumatic stress symptoms: a confirmatory factor analysis of DSM-IV symptom clusters and other symptom models

Recent exploratory [Taylor. S., Kuch, K., Koch, W. J., Crockett, D. J., & P assey, G. (1998). The structure of posttraumatic stress symptons. Journal o f Abnormal Psychology, 107, 154-160.] and confirmatory [Buckley, T. C., Bla nchard, E. B., & Hickling, E. J. (1998). A confirmatory factor analysis of posttraumatic stress symptons. Behaviour Research and Therapy, 36, 1091-109 9; King, D. W., Leskin, G. A., King, L. A., & Weathers, F. W. (1998). Confi rmatory factor analysis of the clinician-administered PTSD scale: evidence for the dimensionality of posttraumatic stress disorder. Psychological Asse ssment, 10, 90-96.] factor analytic investigations suggest that the three s ymptom clusters of posttraumatic stress disorder (PTSD) as defined in the D iagnostic and Statistical Manual [4th ed.; DSM-IV; American Psychiatric Ass ociation (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author.] may not provide the best conceptualization of symptom dimensionality. However, the alternative models have not been in agreement, nor have they been compared against each other or models based on the DSM-IV. The purpose of the present investigation was to test a serie s of dimensional models suggested by these recent factor analytic investiga tions and the DSM-IV. Using data collected with the PTSD Checklist--Civilia n Version [Weathers, F. W., Litz, B. T., Huska, J. A., & Keane, T. M. (1994 ). PCL-C for DSM-IV. Boston: National Center for PTSD--Behavioral Science D ivision.] from 349 referrals to a primary care medical clinic, we used conf irmatory factor analysis to evaluate a: (1) hierarchical four-factor model, (2) four-factor intercorrelated model, (3) hierarchicalthree-factor model, (4) three-factor intercorrelated model, and (5) hierarchical two-factor mo del. The hierarchical four-factor model (comprising four first-order factor s corresponding to reexperiencing, avoidance, numbing, and hyperarousal all subsumed by a higher-order general factor) provided the best overall fit t o the data; although, all models met some standards specified for good mode l fit. More research is needed to establish the dimensional nature of PTSD symptoms and to assess whether identified dimensions differ as a function o f the trauma experience. Implications for assessment, diagnosis, and treatm ent are also discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.