Validity and utility of instruments for screening of depression in women attending antenatal clinics in Blantyre district in Malawi
Introduction: Screening instruments should be brief, valid and easy to use if they are to be useful in a busy antenatal clinic in low-resource settings. A short instrument can be used in a busy antenatal clinic in combination with a more detailed instrument once referred. This study aimed at assessing the validity of a range of depression screening instruments and to test the utility of combining these instruments for use in antenatal clinics in Blantyre district, Malawi.
Methods: This was a sensitivity analysis study using a sub-sample of 97 pregnant women drawn from a cross-sectional study (sample size = 480) that was screening for depression in eight antenatal clinics. Data from the cross-sectional study for the 97 pregnant women on the 3-item screener, Edinburgh Postnatal Depression Scale (EPDS), Hopkins Symptoms Checklist-15 (HSCL-15) and Self-Reporting Questionnaire (SRQ), was compared with a gold standard, the Mini International Neuropsychiatric Interview (MINI). Sensitivity, specificity and area under curve (AUC) were calculated to test for validity of the instruments. The utility of various combinations of the instruments was tested using the compensatory, conjunctive, probability and sequential rules.
Results: The 3-item screener, EPDS, HSCL-15 and SRQ were valid instruments for screening antenatal depression. Sequential combination of the 3-item screener and SRQ had superior discriminant ability over similar combinations of the 3-item screener and either EPDS or HSCL-15 (sensitivity = 78%, specificity = 88%, AUC = 0.885).
Discussion: The 3-item screener, EPDS, HSCL-15 and SRQ are valid instruments for screening depression in local antenatal clinics. The sequential combination of the 3-item screener and SRQ may be a practical, accurate and suitable method for multistage screening of depression in antenatal clinics in Blantyre district, Malawi.
Keywords: Antenatal, depression, screening instrument, utility, validity