Factorial structure and psychometric properties of The Pain Anxiety Symptoms Scale (PASS-20)

The Pain Anxiety Symptoms Scale (PASS-20) has been developed as a general measure of anxiety and fear in individuals with various chronic pain disorders by McCracken and Dhingra (2002). Short-Form scale of PASS-20 has been extracted from 40 items of DASS which published in 1992. This study aimed (1) to examine the factor structure of a Persian language version of the PASS-20 (IRPASS-20); (2) to examine reliability and construct validity of the IRPASS-20. With regard this objective, Persian version of PASS-20 along with The Tampa scale for Kinesiophobia TSK scale, pain catastrophizing scale (PCS), depression and anxiety scales of DASS-21, pain self-efficacy beliefs and pain behavior questionnaire administrated amongst 310 injured worker at a big industrial company. A result of exploratory factor analysis with maximum likelihood extraction method and oblimin rotation has been showed a three factorial solation with 55.3 percentage of variance. Confirmatory factor analyses showed that all the three-factor solutions tested met the minimum acceptable fit criterion. The results of correlation analysis among PASS-20 and its subscales TSK scale, PCS, scales of DASS-21, pain self-efficacy beliefs and pain behavior questionnaire support both the convergent and divergent validity. The findings provide preliminary support for the reliability and validity of the IRPASS-20.