Factor structure of the Edinburgh Postnatal Depression Scale in a population-based sample.

Area of Science:

• Psychological assessment
• Mental health research
• Perinatal psychology

Background:

• Questionnaire validity requires consistent construct measurement across groups and time.
• The Edinburgh Postnatal Depression Scale (EPDS) was intended as unidimensional, but factor analyses have yielded inconsistent structures.
• Previous EPDS structural findings may be influenced by sample characteristics and administration timing.

Purpose of the Study:

• To examine the factor structure of the Edinburgh Postnatal Depression Scale (EPDS).
• To assess the EPDS structure during pregnancy and postpartum across four distinct time points.
• To analyze a large, population-based sample for robust structural validation.

Main Methods:

• Exploratory and confirmatory factor analysis were performed.
• Data from the Avon Longitudinal Study of Parents and Children (ALSPAC) was utilized (n=11,195–12,166).
• The sample was randomly split, and data from 18 and 32 weeks gestation, and 8 weeks and 8 months postpartum were analyzed.

Main Results:

• A stable 3-factor solution (Depression, Anhedonia, Anxiety) demonstrated optimal model fit across all time points.
• The Depression factor (4 items) explained 43.5–47.2% of the variance.
• Anhedonia (2 items) accounted for 10.5–11.1% and Anxiety (3 items) for 8.3–9.4% of the variance.
• Subscales exhibited good internal reliability (Cronbach's αs: .73–.78).

Conclusions:

• The EPDS reliably measures three related factors: depression, anhedonia, and anxiety.
• The scale demonstrates a stable factor structure throughout pregnancy and the first postnatal year.
• These findings support the validity of the EPDS for assessing maternal mental health in perinatal periods.