BMC Psychiatry (May 2022)
Reliability and validity of depression anxiety stress scale (DASS)-21 in screening for common mental disorders among postpartum women in Malawi
Abstract
Abstract Background Approximately one in five women who have recently given birth suffer from common mental disorder (CMD), particularly depression and/or anxiety. Most available CMD screening tools in most low- and middle-income countries do not screen for more than one mental health problem. Having a screening tool that is free to use, short in assessment time, and used to screen for more than one CMD is appealing in a resource-constrained setting. Method We conducted a criterion validation study of the Chichewa translated and adapted DASS-21 instrument against gold standard diagnoses of depression and anxiety disorders using an independently administered Structured Clinical Interview for DSM-IV (SCID). We compared the performance of the DASS-depression subscale with the Edinburgh Postpartum Depression Scale (EPDS). Internal reliability was reported using both Cronbach’s alpha and ordinal alpha. The DASS-21 and EPDS ability to discriminate cases from non-cases was assessed by receiver operating characteristics (ROC) analysis. We selected cut-off points for DASS-21 and EPDS that maximise both sensitivity and specificity. Results One hundred fifteen participants were administered all the measures. Approximately 11.3% and 14.8% had depression and anxiety diagnoses respectively using SCID. The overall Cronbach’s alpha for the DASS-21 scale was 0.74. The DASS-21 subscales had Cronbach’s alpha values of 0.66, 0.29 and 0.52 for depression (DASS-D), anxiety (DASS-A) and stress (DASS-S), respectively. The ordinal alpha for DASS-D, DASS-A and DASS-S subscales were 0.83, 0.74 and 0.87, respectively. The area under the ROC curve was 0.76 (95% CI: 0.61; 0.91) for DASS-D and 0.65 for DASS-A. At a cut-off point of one or more, the sensitivity and specificity for DASS-D were 69.2% and 75.5%, whilst DASS-A was 52.9% and 75.5%, respectively. Pearson correlation coefficient for the association between DASS-D and EPDS was r = 0.61, p < 0.001. Conclusion The DASS-21 had good internal reliability (Cronbach’s alpha), and its ordinal alpha demonstrated good internal reliability for all its sub-scales. Regarding the criterion validation, only the DASS-D and EPDS demonstrated a satisfactory ability to discriminate cases from non-cases. Our findings suggest that health practitioners can use DASS-D as an alternative tool in screening depression as it has fewer questions than EPDS.
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