Grant: Doctoral Award - Frederick Banting and Charles Best Canada Graduate Scholarships

Children of mothers with depression are six times more likely to develop depression themselves. According to the "HPA programming hypothesis," these children are at such high risk for depression because i) the stress system is "programmed" by maternal stress and behavior early in life, and ii) dysregulated stress responses contribute to the onset and maintenance of depression. However, studies have been unable to consistently link maternal depression to children's stress response patterns, suggesting that this relationship is influenced by other factors. My Master's research found that maternal depression has a greater influence on the stress system of infants with certain genetic characteristics, relative to infants without such characteristics. Other research suggests that maternal depression does not adversely impact the infant stress system if the mother and infant have a secure attachment. My PhD research will build on these findings and examine i) the influences of maternal depression, infant genetic characteristics, and infant-mother attachment on infant stress system dysregulation, and ii) whether such dysregulation predicts emotional and behavioral problems in later childhood. I will utilize two longitudinal samples of mother-infant dyads: i) a community sample of 314, and ii) a sample of 550, which includes a high proportion of clinically depressed mothers. Maternal depression and child behavioral and emotional problems were assessed with questionnaires. Cheek cells were assessed for genetic characteristics. Infant saliva was collected during toy frustration and maternal separation challenges in infancy, and was assessed for stress hormone levels. I was trained in, and will rate the quality of mother-infant attachment based on the separation challenge. This study will inform preventative interventions by elucidating the mechanisms through which maternal depression impacts the infant stress system, and later emotional and behavioral problems.