Comparative assessment of Patient Health Questionnaire-9 and Edinburgh Postnatal Depression Scale for screening antenatal depression among Chinese pregnant women.

Background: The Patient Health Questionnaire-9 (PHQ-9) and Edinburgh Postnatal Depression Scale (EPDS) are commonly used for assessing antenatal depression in China. However, clear guidelines for their application are lacking in China, leading to inconsistencies in prenatal mental health care. This study compares the psychometric properties of these scales to improve early detection and intervention strategies for antenatal depression.

Methods: The cross-sectional study included 44,220 women receiving prenatal care from January 1, 2020, to January 31, 2024. All the participants underwent a psychological screening during their maternity check-ups at the Shenzhen Baoan Women's and Children's Hospital, China. We evaluated the reliability, construct validity, and concurrent validity of the two scales using internal consistency indices, factor structures, correlations, and Cohen's kappa.

Results: Both the PHQ-9 (Cronbach's α = 0.800) and EPDS (α = 0.783) demonstrated good internal consistency. The correlation between PHQ-9 and EPDS scores was moderate (ρ = 0.61). Exploratory factor analysis (EFA) revealed a two-factor structure for each scale. When combining all items from both scales, EFA identified four factors: "somatic symptoms," "negative cognitive bias and suicidal ideation," "anxiety and depression," and "anhedonia." The agreement was generally fair across various cutoff scores, with the highest Cohen's kappa being 0.493.

Conclusions: Both the EPDS and PHQ-9 exhibit strong internal consistency in screening for antenatal depression in China. While the EPDS emphasizes "depression and anxiety," the PHQ-9 focuses on "somatic symptoms," suggesting that combining the two may improve detection. Adjusting EPDS cutoff scores and incorporating the PHQ-9 could further enhance screening accuracy.