Purpose
This study aimed to evaluate the psychometric properties of the Depression Anxiety Stress Scales 21 and 12 in a Korean population.

Methods
The Depression Anxiety Stress Scales were translated into Korean using a translation and back-translation technique, and the content validity was assessed by an expert panel. Participants were recruited from six community health centers (n = 431) and two community mental health centers (n = 50). A field test of the psychometric properties of the instruments was conducted using confirmatory factor analysis with bootstrap maximum likelihood estimation involving 1,000 samples, Pearson's analysis, t test, and Cronbach's α coefficient.

Results
Confirmatory factor analysis of the Depression Anxiety Stress Scales 21 and 12 supported both three-factor and second-order three-factor models. The Scales 21 and 12 satisfied convergent validity with the Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, and Perceived Stress Scale-10 and discriminant validity with the Rosenberg Self-Esteem Scale. The scores for the Depression Anxiety Stress Scales 21 and 12 were higher for the psychiatric group than for the nonpsychiatric group, confirming the presence of known-groups validity. The Depression Anxiety Stress Scales 21 and 12 exhibited moderate-to-strong correlations with the Negative Affect. Cronbach's α coefficients for the Depression Anxiety Stress Scales 21 and 12 were .93 and .90, respectively.

Conclusion
The Depression Anxiety Stress Scales 21 and 12 appear to be acceptable, reliable, and valid instruments. However, the shorter Depression Anxiety Stress Scales 12 may be more feasible to use in a busy practice and also be less burdensome to respondents.