Psychometric evaluation and normative data for the depression, anxiety, and stress scales-21 (DASS-21) in a nonclinical sample of U.S. adults.

Health care professionals are coming under increased pressure to empirically monitor patient outcomes across settings as a means of improving clinical practice. Within the psychiatric and primary care communities, many have begun utilizing brief psychometric measures of psychological functioning to accomplish these goals. The purpose of this study was to evaluate the psychometric properties and clinical utility of the Depression, Anxiety, and Stress Scales-21-item version (DASS-21), and contribute normative data to facilitate interpretation using a sample of U.S. adults (N = 503). Item-scale convergence was generally supported, although assumptions of item-scale divergence were not met. Only 86%, 50%, and 43% of Depression, Anxiety, and Stress items, respectively, correlated significantly greater with their hypothesized scales than other scales. Internal consistency reliability was acceptable for all scales and comparable to existing research (αs = .91, .80, and .84 for Depression, Anxiety, and Stress, respectively). Scale-level correlations were greater than what has been reported elsewhere (range of rs = .68 to .73), and principal components analysis supported the extraction of only one component accounting for 47% of the item-level variance. However, confirmatory factor analysis (CFA) favored a three-factor structure when compared to a one-factor model. The implications for the health care professions are discussed.