The validation of the Polish version of the Posttraumatic Diagnostic Scale and its factor structure

BACKGROUND: Posttraumatic Diagnostic Scale (PDS) is a self-descriptive measure developed to provide information regarding posttraumatic stress disorder (PTSD) diagnosis and symptom severity. OBJECTIVES: The aim of this article is to report on the validation of the Polish version of PDS and to test its factor structure with reference to two models: an original three-factor model (Reexperiencing, Avoidance, and Arousal) and alternative five-factor model (Reexperiencing, Avoidance, Numbing, Dysphoric Arousal, and Anxious Arousal). METHOD: The validation procedure included three studies conducted on samples of separate populations: university-level students (n=507), individuals who had experienced various traumas (n=320), and treatment-seeking survivors of motor vehicle accidents (MVA) (n=302). Various other measures of trauma-related psychopathology were administered to participants, as well as the PTSD module of the Structured Clinical Interview (SCID) in the case of MVA patients. RESULTS: PDS showed high internal consistency and test–retest reliability, good diagnostic agreement with SCID, good sensitivity but relatively low specificity. The satisfactory convergent validity was supported by a large number of significant correlations with other measures of trauma-related psychopathology. Confirmatory factor analysis (CFA) generally confirmed both the three-factor structure and the alternative five-factor structure of the questionnaire. CONCLUSIONS: The results show generally good psychometric properties of the Polish version of PDS.