Validation of Persian Version of the Penn State Worry Questionnaire among Multiple Sclerosis Patients

Worry is a common psychological construct in multiple sclerosis (MS). In previous studies, there is little data about the psychometric properties of the measurement tools in population of MS patients. Thus, the present study was performed to validate Penn State Worry Questionnaire (PSWQ) as a common tool for measuring worry.
The research design was cross-sectional for a validation study. It included two groups of MS patients (n=80) and their healthy counterparts (n=80) which were sampled by purposive method and matched by demographic factors. The study population consisted of all patients member of the MS Society of Guilan province in 2011-2012. The internal consistency reliability, construct, concurrent, predictive and differential validity of PSWQ was assessed Also the subjects were evaluated in terms of symptoms of depression, anxiety, obsessive compulsive and General Severity Index (GSI) in Symptom Checklist 90 Revised (SCL-90-R) and neuroticism in NEO Five Factor inventory (NEO-FFI).
The internal consistency of PSWQ was appropriate (α=0.74). The item-total correlation coefficient was better for general worry factor and was in range of 0.21 to 0.60. Results of concurrent validity indicated that PSWQ has a significant relationship with all constructs associated with research tools (P≤0.001). Moreover, PSWQ predicted a significant proportion of the psychopathological symptoms scores and neuroticism variance, even after controlling for confounders. Finally, discriminant analysis model showed that PSWQ can differentiate the two groups of patients and healthy counterparts according to worry level and its overall classification accuracy is 63.1%.
PSWQ have good psychometric properties in the studied MS patients and can be used in clinical settings and related research.