Pii: S0005-7967(99)00061-3

Recent exploratory [Taylor, S., Kuch, K., Koch, W. J., Crockett, D. J., & Passey, G. (1998). The structure of posttraumatic stress symptons. Journal of Abnormal Psychology, 107, 154±160.] and con®rmatory [Buckley, T. C., Blanchard, E. B., & Hickling, E. J. (1998). A con®rmatory factor analysis of posttraumatic stress symptons. Behaviour Research and Therapy, 36, 1091±1099; King, D. W., Leskin, G. A., King, L. A., & Weathers, F. W. (1998). Con®rmatory factor analysis of the clinicianadministered PTSD scale: evidence for the dimensionality of posttraumatic stress disorder. Psychological Assessment, 10, 90±96.] factor analytic investigations suggest that the three symptom clusters of posttraumatic stress disorder (PTSD) as de®ned in the Diagnostic and Statistical Manual [4th ed.; DSMIV; American Psychiatric Association (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 series of dimensional models suggested by these recent factor analytic investigations and the DSM-IV. Using data collected with the PTSD ChecklistÐCivilian Version [Weathers, F. W., Litz, B. T., Huska, J. A., & Keane, T. M. (1994). PCL-C for DSM-IV. Boston: National Center for PTSDÐBehavioral Science Division.] from 349 referrals to a primary care medical clinic, we used con®rmatory factor analysis to evaluate a: (1) hierarchical four-factor model, (2) four-factor intercorrelated model, (3) hierarchical Behaviour Research and Therapy 38 (2000) 203±214 0005-7967/00/$ see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S0005-7967(99)00061-3 www.elsevier.com/locate/brat * Corresponding author. Clinical Research and Development Program, Regina Health District, 2180 23rd Avenue, Regina, Saskatchewan, S4S 0A5, Canada. Tel.: +1-306-766-5384; fax: +1-306-766-5530. E-mail address: [email protected] (G.J.G. Asmundson) three-factor model, (4) three-factor intercorrelated model, and (5) hierarchical two-factor model. The hierarchical four-factor model (comprising four ®rst-order factors corresponding to reexperiencing, avoidance, numbing, and hyperarousal all subsumed by a higher-order general factor) provided the best overall ®t to the data; although, all models met some standards speci®ed for good model ®t. More research is needed to establish the dimensional nature of PTSD symptoms and to assess whether identi®ed dimensions di€er as a function of the trauma experience. Implications for assessment, diagnosis, and treatment are also discussed. # 2000 Elsevier Science Ltd. All rights reserved.