The interplay of maternal and paternal postpartum depressive symptoms with children's internalizing and externalizing symptoms from childhood to adolescence: does socioeconomic status matter? A longitudinal cohort study

Background Maternal postpartum depression is an important risk factor for internalizing and externalizing problems in children. The role of concurrent paternal depression remains unclear, especially by socioeconomic status. This study examined independent and interactive associations of postpartum maternal and paternal depression with children's internalizing/externalizing symptoms throughout childhood and adolescence (ages 3.5–17 years). Methods We used data from the Québec Longitudinal Study of Child Development, a representative birth cohort (1997–1998) in Canada. Data included self‐reported maternal and paternal depressive symptoms at 5 months' postpartum using the Center for Epidemiologic Studies Depression Scale. Internalizing and externalizing symptoms in children were reported by parents, teachers and children/adolescents using the Social Behaviour Questionnaire (ages 3.5–13 years) and the Mental Health and Social Inadaptation Assessment for Adolescents (ages 15–17 years). We used three‐level mixed effects modelling to test associations after adjusting for confounding factors. Results With 168 single‐parent families excluded, our sample consisted of 1,700 families with useable data. Of these, 275 (16.2%) families reported maternal depression (clinically elevated symptoms), 135 (7.9%) paternal depression and 39 (2.3%) both. In families with high socioeconomic status, maternal depression was associated with greater child internalizing (β = .34; p < .001) and externalizing symptoms (β = .22; p = .002), regardless of the presence/absence of paternal depression. In families with low socioeconomic status, associations with symptoms were stronger with concurrent paternal depression (internalizing, β = .84, p < .001; externalizing, β = .71, p = .003) than without (internalizing, β = .30, p < .001; externalizing, β = .24, p = .002). Conclusions Maternal depression increases the risk for children's internalizing/externalizing problems in all socioeconomic contexts. In families with low socioeconomic status, risks were exacerbated by concurrent paternal depression. Postpartum depression, especially in low socioeconomic environments, should be a primary focus to optimize mental health across generations.