Abstract
Breast cancer impacts the psychological well-being of women, leaving them at risk of developing depression, anxiety, and other stress-related disorders. The Depression Anxiety Stress Scales (DASS-21) is a widely used measure, although empirical evidence regarding its psychometric properties in the breast cancer population is limited. The purpose of this study was to conduct an exhaustive analysis of the psychometric properties of the DASS-21 in a sample of Spanish women diagnosed with breast cancer. Participants were 289 breast cancer patients who completed the DASS-21 and other questionnaires measuring life satisfaction, positive and negative affect, flourishing, perceived stress, and breast cancer-specific stressors. In terms of validity evidence based on the internal structure of the DASS-21, adequate fit indices were obtained for the model based on three first-order factors (depression, anxiety, stress) and one second-order factor (general psychological distress). Reliability coefficients (McDonald’s omega) ranged from .84 to .95. Validity evidence based on relationships with other variables was also provided by moderate and strong correlations with well-being indicators and stress measures. The results support the use of the DASS-21 for measuring general psychological distress in the breast cancer context, where it may provide useful information for the design of psychological interventions with patients.