Validation of screening tools for antenatal depression in Malawi--a comparison of the Edinburgh Postnatal Depression Scale and Self Reporting Questionnaire

BACKGROUND: The detection of antenatal depression in resource-limited settings such as Malawi, Africa, is important and requires an accurate and practical screening tool. It is not known which questionnaire would be most suitable for this purpose.

METHOD: A rigorously translated and modified Chichewa version of the Edinburgh Postnatal Depression Scale (EPDS) was developed. The Chichewa EPDS and an existing Chichewa version of the Self Reporting Questionnaire (SRQ) were validated in women attending an antenatal clinic in rural Malawi, using DSM-IV major and major-or-minor depressive episode as the gold standard diagnoses, determined with Structured Clinical Interview for DSM-IV (SCID). Weighted test characteristics for each possible cut-off were calculated and Receiver Operator Characteristic (ROC) curves derived.

RESULTS: The participants were 224 pregnant women, 92 of whom were interviewed using the SCID. The area under the ROC curve (AUC) for detection of current major depressive disorder for the EPDS was 0.811 (95% CI 0.734-0.889) and for the SRQ was 0.833 (95% CI 0.770-0.897). AUC for major-or-minor depressive disorder for the EPDS was 0.767 (95% CI 0.695-0.839) and for the SRQ was 0.883 (95% CI 0.839-0.927). These were not significant differences. Internal consistency was high for both the SRQ (Cronbach's alpha 0.825) and the EPDS (Cronbach's alpha 0.904).

LIMITATIONS: Inter-rater reliability testing was not done. The relatively small sample size resulted in wide confidence intervals around AUCs. The study was conducted amongst antenatal clinic attenders only, limiting generalisability to all pregnant women in this setting.

CONCLUSION: The Chichewa versions of the EPDS and SRQ both show utility as brief screening measures for detection of antenatal depression in rural Malawi.