To examine relations between maternal depression (in pure and comorbid forms) and mother–infant interactions, infant attachment, and toddler social-emotional problems and competencies. A second objective was to explore sex differences.

Sixty-nine mother–infant dyads were followed from pregnancy to 30 months postpartum. Depression was measured at multiple times with self-report and interview assessments. Play was assessed at 4 months and attachment status at 14 months postpartum. At 30 months, mothers completed the Child Behavior Checklist and Infant-Toddler Social and Emotional Assessment.

Lifetime maternal depression predicted less optimal mother–infant interactions and insecure infant attachment. However, this “depression effect” was accounted for by mothers with comorbid diagnoses, who had less optimal interactions, and infants with higher rates of insecurity than either mothers with depression only or mothers with no psychopathology. Prenatal and postpartum depressive symptoms were associated with problem behaviors and lower competencies for boys. In contrast, quality of early interactions predicted problem behaviors in girls.

It is important to examine the context of maternal depression with respect to additional psychopathology and environmental risks. Maternal depression in the presence of other psychopathology confers risk to the mother–child dyad. Consistent with previous work, risk pathways appear to differ for boys and girls. Early identification and prevention efforts are warranted.