Validation of the Mainland Chinese version of the Edinburgh Postnatal Depression Scale in Chengdu mothers

Background: The Mainland Chinese version of the Edinburgh Postnatal Depression Scale (EPDS) has been validated among antenatal women, subsequent validation among postnatal women is necessary.

Objectives: This study investigated the prevalence of postnatal depression and the psychometric characteristics of the Mainland Chinese version of the EPDS among postnatal women.

Design: Two studies were used for validating the EPDS with specific aims. Study I established the psychometric properties of the EPDS by examining the convergent, discriminant and construct validity, internal consistency and stability of the scale. Study II established its sensitivity, specificity and the optimal cut-off score of the EPDS according the DSM-IV-TR criteria using the Structured Clinical Interview.

Setting: : Four regional public hospitals in Chengdu.

Participants: : A convenience sample was composed of 300 and 342 postnatal women in study I and II, respectively.

Method: A receiver operating characteristic (ROC) analysis was carried out to evaluate the global functioning of the scale. The Beck Depression Inventory (BDI), Dyadic Adjustment Scale (DAS) and standard SF-12 Health Survey (SF-12) were used to investigate the convergent, discriminant and construct validity. An exploratory factor analysis was used to investigate the structural validity of the scale. Confirmatory factor analysis (CFA) was tested the proposed factor module by Linear Structural Relations (LISREL). The Cronbach's alpha reliability coefficient, split-half reliability and test-retest reliability were used to examine the internal consistency and stability of the scale.

Results: The prevalence of postnatal depression was 4.7%. Structural validity revealed a three-factor structure for the EPDS and the CFA showed a good overall fit of this three-factor model. Convergent and construct validity was supported and discriminant validity suggested that the EPDS successfully discriminated among the nondepressed, mildly and clinically depressed groups. The area under curve (AUC) was 89.6% and the logistic estimate for the threshold score was 10.5 (sensitivity, 81.25%; specificity, 80.67%) for clinical depression. The split-half reliability of the EPDS was 0.74, Cronbach's alpha was 0.78 and test-retest reliability was 0.90.

Conclusions: Our data confirm the validity of the Mainland Chinese version of EPDS in identifying postnatal depression among postnatal women in Chengdu by using >10 cut-off point. Because of its brevity and acceptability, it is recommended that the EPDS be used in routine postnatal screening.