Abstract
Children who have been adopted internationally commonly experience institutional care and other forms of adversity prior to adoption that can alter the functioning of the hypothalamic–pituitary–adrenal (HPA) axis. In particular, internationally adopted children tend to have blunted diurnal declines compared to children raised in their birth families. The Attachment and Biobehavioral Catch-Up (ABC) intervention was developed to enhance young children's biological and behavioral regulation by promoting sensitive parenting. The current study used a randomized controlled trial to assess whether ABC improved the diurnal functioning of the HPA axis among 85 children who had been adopted internationally when they were between the ages of 4 and 33 months (M = 16.12). Prior to the intervention, there were no significant differences in diurnal cortisol production between children whose parents were randomly assigned to receive ABC and children whose parents were randomly assigned to receive a control intervention. After the intervention, children whose parents had received the ABC intervention exhibited steeper declines in cortisol levels throughout the day than children whose parents had received the control intervention. These results indicate that the ABC intervention is effective in enhancing a healthy pattern of diurnal HPA axis regulation for young children who have been adopted internationally.