Psychometric Properties of the Persian Version of the Padua Inventory: PPI-WSUR Non-Clinical Student Sample

Article excerpt

Objective: The psychometric properties and factor structure of the Persian Padua Inventory (PPI), a measure of obsessive- compulsive phenomena, was examined in a non-clinical sample of 348 Iranian university students.

Method: The PPI was translated into Persian, and its back translation was controlled by the author inventory. A pilot study based on cultural differences was carried out on twenty students. The study subjects consisted of 348 university students, and they completed PPI, OCI-R, MOCI, BAI, STAI, BDI-II and the demographic inventory.

Result: The factor analysis of the PPI, exhibited eight factors similar but not identical with factor structure in previous studies. as the eight factors are as follows: contamination obsessions; washing compulsions; ordering compulsions; checking compulsions; obsessional thoughts to harm self/others; obsessional thoughts about violence; obsessional impulses to harm self/others; and obsessional impulses to steal. The result also indicated excellent internal consistency (Cronbach alpha= 0.92), Spearman split 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).

Conclusion: The Iranian version of the PI to some extend remains the sound psychometric properties of the original version..

Keywords: Obsessive compulsive disorder (OCD), assessment (... assessment), Padua Inventory (PI-WSUR), Iranian, Persian (Persian ...)

Iran J Psychiatry 2011; 6:12-18

Several theoretical and psychometrically sound measures have been developed to assess the presence and severity of OCD symptoms in community and clinical samples. Each type of instrument has unique strengths and weaknesses. Multiple methods of assessment are commonly used for OCD and spectrum conditions, including formal diagnostic interviews, as well as interviews for gathering clinical information.

At present, various self-report instruments are available to assist in the diagnosis and measurement of OCD. The most widely accepted measures are: Leyton Obsessional inventory short form (LOI) (1); The Maudsley Obsessive-Compulsive Inventory (MOCI) (2); Padua Inventory-Washington State University Revision (PI) (3,4);Yale-Brown Obsessive-Compulsive Scale-self-report (Y-BOCS-SR) (5); Obsessive- Compulsive Inventory-Revised (OCI-R) (6); Vancouver Obsessional compulsive inventory (VOCI) (7); Florida obsessive-compulsive inventory (FOCI) (8); Schedule of compulsions, obsessions, and pathological impulses (SCOPI,) (9); (CBOCI) (10). Nonetheless, those measures have several shortcomings, in terms of content or psychiatric properties that limit their use in both clinical and research settings (11, 12). Some researchers have

investigated sub-types of OCD symptoms (13-15); there is also an emerging consensus in the field that OCD is better conceptualized according to the dimensional model (16). Recently, Lee (17) proposed a model of obsessive thoughts that is pertinent to theories of OCD as proposed by Rachman (18-20). They suggested that obsessive thoughts can be classified into two types of autogenous obsessions.

Sanavio (3) developed the original Padua Inventory as the first major of self reported OCD symptoms. The original Italian version of the PI added two obsessive factors to the two traditional cleaning and checking scales. The replication of the research across different cultures requires the use of a measure that has been standardized across those cultural contexts. It was a self report inventory that assessed the degree of disturbance or difficulty of 60 different thoughts and behaviors engendered for the individual with OCD. The PI has been adopted in different countries.

Some researches showed that PI also measures "worry" in addition to "obsessions".

The result from Kyrios, Bhar and Wade (21) study indicated that the PI exhibited a similar but not identical factor structure compared to previous studies. …