Edinburgh Postnatal Depression Scale Factor Structure and Invariance in Fathers Across the First Two Postnatal Years: Evidence for a Three-Factor Model and Elevated Screening Positivity in Year 2

The dimensional structure of the Edinburgh Postnatal Depression Scale (EPDS) in fathers remains debated, and it is unclear whether scale properties are comparable as children age through the first 2 years. This study aims to examine the EPDS factor structure and measurement invariance across infant age bands among Swedish fathers. We analyzed 2,318 EPDS assessments from 1,615 fathers when their child was 0 to 24 months (0–6: n = 597; 7–12: n = 701; 13–18: n = 485; 19–24: n = 535). Competing confirmatory factor analyses compared one-, two-, and three-factor models within each age band. We then tested measurement invariance across bands. EPDS cut-off ≥10 described screening-positive proportions. A three-factor model: anhedonia (items 1–2), anxiety (3–6), and depressive affect (7–10) outperformed one- and two-factor alternatives across all age bands, with acceptable-to-good fit. Latent factors were positively and substantially inter-correlated. Strict measurement invariance was supported across age bands, indicating that mean-level comparisons are defensible as children age. Using EPDS ≥ 10, the proportion screening positive was 16.75% (0–6 months), 20.26% (7–12), 26.39% (13–18), and 22.99% (19–24). Internal consistency for the total scale was good across bands. In a national cohort of Swedish fathers across the first two postnatal years, the EPDS showed a replicable three-factor structure and strict invariance across child-age bands, supporting valid comparisons over time. Screening yields non-trivial prevalence beyond 12 months, underscoring the value of father-inclusive screening into the second postnatal year.