A Study of Validity and Reliability of the Persian Version of the Padua Inventory-Washington State University Revision (PI-WSUR) in a Sample of Healthy Iranian Students

Evaluation of the validity of the factor structure of Persian Padua Inventory (PPI) (a measure of obsessive-compulsive phenomena) on a sample of 348 non-clinical students of Tehran University, School of Medicine. Subsequent to translating the questionnaire to Persian and its back translation to original language and final control by the author of the inventory (Burns), a pilot study based on cultural differences was carried out on twenty students. The total subjects participating in this study comprised of 348 individuals in the age range of 18-44 years. The subjects completed PPI, OCI-R, MOCI, BAI, STAI, BDI-II and demographic inventory. The factor analysis of the PPI exhibited eight factors similar but not identical to previous studies: contamination obsessions, washing compulsions, ordering compulsions, checking compulsions, obsessive thoughts about harm to self/others, obsessive thoughts about violence, obsessive impulses to harm self/others, and obsessive impulses to theft. The results of the present study indicate reliability and internal consistency (Cronbach’s alpha= 0.92), Spearman splite test (0.95) and test- retest (r=0.77). We assessed the concurrent validity of the PPI in relation to the Obsessive Compulsive Inventory-Revised (OCI-R), and the Maudsley Obsessive- Compulsive Inventory (MOCI) and the results were 0.69 and 0.58 respectively. In correlation with its original version, the PPI is a relatively reliable and valid questionnaire in Iran.