Does mothers' postnatal depression influence the development of imitation?

Background: Links between mothers' postnatal depression (PND) and children's cognition have been identified in several samples, but the evidence is inconsistent. We hypothesized that PND may specifically interfere with infants' imitation, an early learning ability that features in early mother-infant interaction and is linked to memory, causal understanding and joint attention. 

Methods: A randomly controlled experiment on imitation was embedded into a longitudinal study of a representative sample of firstborn British infants, whose mothers were assessed for depression using the SCAN interview during pregnancy and at 6 months postpartum. At a mean of 12.8 months, 253 infants were presented with two imitation tasks that varied in difficulty, in counterbalanced order. 

Results: The infants of mothers who experienced PND were significantly less likely than other infants in the sample to imitate the modelled actions, showing a 72% reduction in the likelihood of imitation. The association with PND was not explained by sociodemographic adversity, or a history of depression during pregnancy or prior to conception. Mothers' references to infants' internal states during mother-infant interaction at 6 months facilitated imitation at 12 months, but did not explain the link with PND. 

Conclusions: The findings support the hypothesis that associations between PND and later cognitive outcomes may partly derive from effects of the mother's illness on infants' early learning abilities. Support for infants' learning should be considered as an age-appropriate, child-focused component of interventions designed to ameliorate the effects of PND.

Neurodevelopmental and respiratory follow-up results at 7 years for children from the United Kingdom and Ireland enrolled in a randomized trial of early and late postnatal corticosteroid treatment, systemic and inhaled (the Open Study of Early Corticosteroid Treatment)

The goals were to compare early school-age neurodevelopmental and respiratory outcomes for children who were treated with either early (15 days) postnatal corticosteroid therapy and to compare systemic dexamethasone treatment with inhaled budesonide treatment.

Mothers' antenatal depression and their children's antisocial outcomes

Interviews of 120 British adolescents and their parents (80% of a random sample of antenatal patients drawn from a representative urban population and followed longitudinally) revealed that 40 (33%) had been arrested and/or had a diagnosis of DSM-IV conduct disorder by 16 years of age; of those, 18 (45%) had committed violent acts. Depression in pregnancy significantly predicted violence in adolescence, even after controlling for the family environment, the child's later exposure to maternal depression, the mother's smoking and drinking during pregnancy, and parents' antisocial behavior. Mothers with a history of conduct problems were at elevated risk to become depressed in pregnancy, and the offspring of depressed women had a greater chance of becoming violent by age 16.