Psychometric properties of the perceived stress scale (pss-10) with breast cancer patients.

Breast cancer diagnosis is one of the most difficult events that a woman can experience during her life and it usually produces high levels of stress. Global measures of perceived stress are useful for screening and for comparing stress levels between cancer patients and other clinical and nonclinical populations. One such instrument that is widely used is the Perceived Stress Scale (pss-10), but its psychometric properties have scarcely been analysed with breast cancer patients. The aim of this study was to provide validity evidence regarding the use of the 10-item version of the pss-10 as a tool for measuring perceived stress in this context. Participants were 215 Spanish breast cancer patients who completed the PSS-10 and the DASS-21, a measure of affective distress (depression, anxiety, and stress). The internal structure of the PSS-10 was examined through confirmatory factor analysis (CFA), and the reliability of test scores was estimated using McDonald's omega coefficient. Validity evidence based on relationships with other variables was also obtained using correlation analysis. The CFA supported a correlated two-factor structure: perceived helplessness (six negatively worded items) and perceived self-efficacy (four positively worded items). Reliability coefficients for scores on these two factors were 0.87 and 0.73, respectively. Scores on affective distress (DASS-21) were strongly and positively correlated with perceived helplessness and moderately and negatively correlated with perceived self-efficacy. The PSS-10 is an adequate tool for measuring perceived stress in the breast cancer context and it may be useful for identifying women at risk of psychological maladjustment.