A comparison of the long and short forms of the Penn State Worry Questionnaire in adults with generalised anxiety disorder

The Penn State Worry Questionnaire (PSWQ) is a 16-item self-report measure designed to assess pathological worry. The PSWQ has, however, demonstrated inconsistent factor structure in adults and older adults leading to the development of the 8-item PSWQ-A and the ultra-brief 3-item PSWQ-3. The PSWQ is yet to be compared to the PSWQ-A and PSWQ-3 in adults with generalised anxiety disorder (GAD). Thus, the current study aimed to evaluate the psychometric properties of these three versions. Participants were screened using the Anxiety Disorders Interview Schedule for DSM-IV-TR to ascertain clinical principal diagnosis of GAD (n = 140) or non-clinical status (n = 76). Four different confirmatory factor models were fit to the 16-item PSWQ, with a unidimensional model fit to the 8-item PSWQ-A and to the PSWQ-3. A bifactor model fitted the data best for the PSWQ, and a unidimensional PSWQ-A model fitted the data best for the GAD sample. Results found that all three versions of the PSWQ demonstrated good construct validity, moderate test-retest reliability, and excellent criterion validity. ROC curve analysis indicated that all three versions demonstrated comparable levels of sensitivity and specificity for screening GAD. Both the PSWQ-A and PSWQ demonstrated no floor or ceiling effects and good internal consistency, whereas the PSWQ-3 demonstrated floor effects with adequate internal consistency. Overall, all three versions of the PSWQ share comparable psychometric properties. As such, the brevity of the PSWQ-A and its comparable performance to the 16-item PSWQ, warrant recommendations for use of this version to researchers and clinicians.