The Edinburgh Postnatal Depression Scale: Model Comparison of Factor Structure and its Psychosocial Correlates Among Mothers at One Month After Childbirth in Japan

Abstract

Background:The Edinburgh Postnatal Depression Scale (EPDS; Cox, Holden & Sagovsky, 1987) has been widely used as a screening instrument. It is also used as a measure of Postnatal Depression (PND) severity. Various EPDS factor structure models have been proposed in many studies without an unequivocal conclusion. We compared first-order, higher-order factor, and bifactor models of the EPDS, and examined possible predictors of subscales by Structural Equation Modelling (SEM).Methods:Data came from a follow-up study of 758 women after childbirth on two occasions (five days and one month postnatal). We used the EPDS together with items tapping Negative Life Events (NLEs) and coping styles and behaviours.Results:The bifactor model showed the best fit with data compared with all other models: CFI = 0.999, RMSEA = 0.14, and AIC = 79.637. A single general dimension alongside three distinct subfactors (anhedonia, anxiety, and dysphoria) was predicted differentially by various predictor variables.Conclusion:Our study expanded on a previous factor structural study of the EPDS and developed the hierarchical (bifactor) model. The model’s construct validity was confirmed by its meaningful associations with NLEs and coping styles and behaviours.