Emerging work has examined parent-child concordance of hypothalamic-pituitary-adrenal (HPA) axis functioning (i.e., adrenocortical concordance) which reflects the attunement or association of the stress hormone cortisol between the parent and child. The cortisol awakening response (CAR) is a critical aspect of HPA axis functioning that is sensitive to environmental factors and uniquely predicts psychopathology in youth. HPA axis functioning has also been linked to alterations in brain structure, specifically the hippocampus. The hippocampus is a critical brain region involved in learning and emotional processing and is sensitive to the parenting context, and undergoes change across early childhood. Despite these critical links between the parent-child dyad, HPA axis functioning, and hippocampal structure, no study has examined the longitudinal outcomes of adrenocortical concordance.

The current study examined early parent-child adrenocortical concordance and its concurrent and longitudinal associations with parenting and children’s psychopathology and psychosocial functioning, as well as its longitudinal associations with children’s hippocampal structure in middle childhood. Participants included 142 parent-child dyads. Parents and children provided cortisol at Wave 1 when children were 3-5 years-old, and 98 dyads returned for the Wave 2 assessment three years later when children were 5-9 years-old. At Wave 1, parents and children provided salivary cortisol samples at waking, and 30 and 45 minutes post-waking across two days to assess the CAR. At Waves 1 and 2, child psychopathology and functioning were assessed through a parent-report clinical interview, and the parenting context was assessed through a laboratory-based parent-child interaction task. At Wave 2, a subsample of 51 children completed an anatomical magnetic resonance imaging assessment to measure hippocampal structure.

Stronger parent-child concordance was associated with children’s poorer outcomes, namely increases in parental hostility from early to middle childhood, and children’s greater psychiatric symptoms and poorer psychosocial functioning in early and middle childhood. Moreover, parent- and child-level risk factors moderated several associations between stronger concordance and children’s poor outcomes. Parent-child concordance was not related to children’s hippocampal volumes in middle childhood. Importantly, our findings highlight adrenocortical concordance as a process underlying the parent-child relationship that plays a role in the development of psychopathology and functional impairment in children.