The contributions of early adverse experiences and trajectories of respiratory sinus arrhythmia on the development of neurobehavioral disinhibition among children with prenatal substance exposure.

Neurobehavioral disinhibition (ND) is a complex condition reflecting a wide range of problems involving difficulties with emotion regulation and behavior control. Respiratory sinus arrhythmia (RSA) is a physiological correlate of emotion regulation that has been studied in a variety of at-risk populations; however, there are no studies of RSA in children with ND. Data were drawn from a prospective longitudinal study of prenatal substance exposure that included 1,073 participants. Baseline RSA and RSA reactivity to an attention-demanding task were assessed at 3, 4, 5, and 6 years. ND was assessed at ages 8/9, 11, and 13/14 years via behavioral dysregulation and executive dysfunction composite measures. Greater exposure to early adversity was related to less RSA reactivity at 3 years, increases in RSA reactivity from ages 3 to 6 years, and increased behavioral dysregulation from ages 8/9 to 13/14. RSA reactivity was examined as a moderator of the association between early adversity and changes in ND. A significant Early Adversity × RSA Reactivity quadratic interaction revealed that children with decelerations in RSA reactivity exhibited increases in behavioral dysregulation, regardless of their exposure to early adversity. However, greater exposure to early adversity was related to greater increases in behavioral dysregulation, but only if children exhibited accelerations in RSA reactivity from ages 3 to 6 years. The results contribute to our understanding of how interactions across multiple levels of analysis contribute to the development of ND.

Disentangling the effects of genetic, prenatal and parenting influences on children's cortisol variability.

Developmental plasticity models hypothesize the role of genetic and prenatal environmental influences on the development of the hypothalamic-pituitary-adrenal (HPA) axis and highlight that genes and the prenatal environment may moderate early postnatal environmental influences on HPA functioning. This article examines the interplay of genetic, prenatal and parenting influences across the first 4.5 years of life on a novel index of children's cortisol variability. Repeated measures data were obtained from 134 adoption-linked families, adopted children and both their adoptive parents and birth mothers, who participated in a longitudinal, prospective US domestic adoption study. Genetic and prenatal influences moderated associations between inconsistency in overreactive parenting from child age 9 months to 4.5 years and children's cortisol variability at 4.5 years differently for mothers and fathers. Among children whose birth mothers had high morning cortisol, adoptive fathers' inconsistent overreactive parenting predicted higher cortisol variability, whereas among children with low birth mother morning cortisol adoptive fathers' inconsistent overreactive parenting predicted lower cortisol variability. Among children who experienced high levels of prenatal risk, adoptive mothers' inconsistent overreactive parenting predicted lower cortisol variability and adoptive fathers' inconsistent overreactive parenting predicted higher cortisol variability, whereas among children who experienced low levels of prenatal risk there were no associations between inconsistent overreactive parenting and children's cortisol variability. Findings supported developmental plasticity models and uncovered novel developmental, gene × environment and prenatal × environment influences on children's cortisol functioning.

Does HPA-Axis Dysregulation Account for the Effects of Income on Effortful Control and Adjustment in Preschool Children?

The effects of low income on children's adjustment might be accounted for by disruptions to hypothalamic-pituitary-adrenal (HPA)-axis activity and to the development of effortful control. Using longitudinal data and a community sample of preschool-age children (N = 306, 36-39 months) and their mothers, recruited to over-represent low-income families, we explored the associations among diurnal cortisol levels and effortful control, and we tested a model in which diurnal cortisol and effortful control account for the effects of family income on child adjustment. Continuous indicators of morning cortisol level and diurnal slope, as well as dichotomous indicators reflecting low morning levels and flat diurnal slope, were examined as predictors of rank-order changes in two dimensions of effortful control, executive control and delay ability. Low income was related to a flat diurnal cortisol slope, and above the effects of family income, a flat diurnal cortisol slope predicted lower social competence. Low morning cortisol level predicted smaller gains in executive control and higher total adjustment problems. Further, delay ability predicted lower adjustment problems above the effects of income and diurnal cortisol levels. The results suggest that HPA-axis dysregulation and effortful control contribute additively to children's adjustment.