Maternal depression is an important risk factor for child behavioral and psychological problems. Both timing and chronicity of depression may interfere with developmental tasks during infancy or the toddler years.

The aim of the present research is to assess whether maternal depression timing and depression trajectories predict child emotional and behavioral problems at 5 years, and to examine whether there are differential effects according to parental socioeconomic status.

Analysis of prospective data from 1183 children participating in the EDEN mother–child cohort study. Maternal depressive symptoms were determined in pregnancy (prenatal); 4, 8 and 12 months after birth (postpartum) and at 3 and 5 years (toddler) using the CESD and EPDS scales. Children's emotional and behavioral problems at age five were assessed using the Strengths and Difficulties Questionnaire (SDQ). Trajectories of maternal depressive symptoms were modeled with a group-based technique. A series of multiple regression models were used to examine the association between maternal depression timing and trajectories and SDQ scores.

Children exposed to maternal depression in the postpartum or toddler period presented more emotional and behavioral problems at age five. The same pattern was found for children exposed to chronic symptoms of maternal depression. Postpartum depressive symptoms were associated with more conduct problems, hyperactivity/inattention and overall problem behavior at age five in children whose mothers had a low educational level.

Maternal depression timing and chronicity may have detrimental emotional and behavioral effects on young children, especially for those from more disadvantaged backgrounds.