Mental health of prison inmates: validation and measurement invariance of the Depression, Anxiety, and Stress Scale (DASS)

The Depression, Anxiety and Stress Scale (DASS-21) is recognized as being a widely used measure for the assessment of negative emotional states. While DASS is being widely used for assessing mental health in Pakistan, limited research has been done regarding its factor structure and measurement invariance. A core aim of the study was to validate, assess the factor structure and measurement invariance of the Depression, Anxiety and Stress Scale (DASS-21) among male and female prison inmates. A sample of 350 inmates with a mean age of 33.23 years with 190 males and 160 females. The results showed excellent Cronbach alpha or internal consistency reliability of the overall scores on DASS and its subscales ranging from (r = .86 to .71). Additionally, the findings showed a good fit of the three factor model and the one factor model of the DASS-21 aimed at assessing psychological distress. Strong measurement invariance was found with regard to gender thus showing that the DASS-21 is understood and interpreted similarly by males and females. For the purpose of assessing the convergent validity, MSV and AVE were calculated and were found to be within the acceptable range. In conclusion, DASS-21 showed good psychometric properties which is evident its excellent internal consistency reliability and in accordance with the model fit indices.