Dev Psychopathol 2018 05 19;30(2):623-634. Epub 2017 Sep 19.
A growing number of research studies have examined the intradyadic coregulation (or attunement) of hypothalamus-pituitary-adrenal axis functioning in mothers and their children. However, it is unclear how early this coregulation may be present in dyads at clinical high risk and whether certain factors, such as maternal depression or positive parenting, are associated with the strength of this coregulation. The present study examined cortisol attunement within mother-infant dyads in a high-risk sample of 233 mothers who received treatment for psychiatric illness during pregnancy and whose infants were 6 months old at the study visit. Results showed that maternal and infant cortisol covaried across four time points that included a stressor paradigm and a mother-infant interaction task. Greater maternal positive affect, but not depression, predicted stronger cortisol attunement. In addition, infants' cortisol level following separation from the mother predicted mothers' cortisol level at the next time point. Mothers' cortisol level following the separation and the laboratory stress paradigm predicted infants' cortisol levels at each successive time point, over and above infants' own cortisol at the previous time point. These findings suggest that maternal and infant cortisol levels influence one another in a bidirectional fashion that may be temporally and context dependent.