Psychometric properties of the 14, 10 and 4-item 'Perceived Stress Scale' among asthmatic patients in Iran

Objective (s): The “Perceived Stress Scale” (PSS) is one of the most widely used instruments for measuring psychological stress in a range of clinical and nonclinical settings. The aim of the present study was to examine the psychometric properties of the all three versions of the PSS (PSS-14, PSS-10, and PSS-4) among asthmatic patients in Iran. Methods: A total of 106 asthmatic patients referring to several clinics in Sanandaj were selected by convenience sampling for this study. The PSS-14 and the short-form version of the “Depression Anxiety and Stress Scale” (DASS-21) were administrated to all participants. The psychometric properties of the PSS were examined: construct validity using confirmatory factor analysis (CFA), convergent validity by evaluating the relationship with DASS-21 and internal consistency using Cronbach’s alpha. Results: The findings of CFA revealed that a two-factor model for all three versions of PSS, containing both negative and positive factors, fit the data significantly better than a one-factor model. The Cronbach’s alpha coefficients for the PSS-14, PSS-10, and PSS-4 were 0.90, 0.90, and 0.77, respectively. All three versions of the PSS were significantly positively correlated with the DASS-21 and its subscales, indicating an acceptable convergent validity. Moreover, women scored higher than men on the PSS. Conclusion: All three versions of the PSS demonstrated adequate psychometric properties for measuring psychological stress among asthmatic patients.