Abstract

The DASS-21 is a questionnaire that measures psychological distress related to symptoms of depression, anxiety and stress. Its usefulness in middle adulthood and the elderly has been scarcely investigated, since previous studies have focused mainly on children and adolescents. The aim of this study was to determine the psychometric properties of the DASS-21 through the analysis of its factorial structure and the relationship with measures of perceived social support and sleep quality in a sample of Chilean adults and elderly people. The bifactor model obtained the best fit to the data [chi(2) (85) = 264.365, p < .001; CFI = .984; TLI = .980; RMSEA = .043 (CI90% .033 - .053); SRMR = .045]; in this, it could be evidenced that the greatest proportion of variance is explained by a general factor of psychological distress. In addition, structural equation modeling provided evidence that psychological distress is inversely related to sleep quality and is influenced by perceived social support. In conclusion, the DASS-21 is a valid, reliable and easy to apply instrument that can be used in adults and older adults in research as well as in the primary clinical approach.