Postpartum depressive symptoms across time and place: Structural invariance of the Self-Reporting Questionnaire among women from the international, multi-site MAL-ED study

Background The Self-Reporting Questionnaire (SRQ) is a screening instrument that has been shown to be an effective measure of depression in postpartum women and is widely used in developing nations. Methods The SRQ was administered to 2028 mothers from eight nations at two time points: one and six months postpartum. All data were obtained from the Interactions of Malnutrition and Enteric Infections: Consequences for Child Health and Development (MAL-ED) study. The sample included women from MAL-ED sites in Bangladesh, Brazil, India, Nepal, Pakistan, Peru, South Africa, and Tanzania. This study examined three aspects of validity of SRQ scores including (a) structural validity, (b) cross-cultural invariance, and (c) invariance over time. Results A 16-item, one-factor structure with items reflecting somatic symptoms removed was deemed to be superior to the original structure in this postpartum population. Although differential item functioning (DIF) across sites was evident the one-factor model was a good fit to the data from seven sites, and the structure was invariant across the one- and six-month time points. Limitations Findings are based on data from self-report scales. No information about the clinical status of the participants was available. Conclusions Overall, findings support the validity of a modified model of the SRQ among postpartum women. Somatic symptoms (e.g., headaches, not sleeping well) may not reflect internalizing problems in a postpartum population. Implications for researchers and practitioners are discussed.