Maternal Postpartum Depression Increases Vulnerability for Toddler Behavior Problems through Infant Cortisol Reactivity

The current study examined the role of hypothalamic-pituitary-adrenal reactivity (a physiological indicator of stress) in early infancy as a mediator of the relationship between maternal postpartum depression and toddler behavior problems. Participants were 137 at-risk mothers and their children participating in a longitudinal study of intergenerational transmission of risk. Mothers' depression was measured five times during the infants' first 18 months. Infant cortisol was collected during a social stressor (the still-face paradigm) when infants were 6 months old, and mothers reported on toddlers' internalizing and externalizing symptoms at 18 months. Among this sample of high-risk mother-infant dyads, early postpartum depression predicted atypical infant cortisol reactivity at Correspondence should be sent to