HPA axis linkage in parent-child dyads: Effects of parent sex, autism spectrum diagnosis, and dyadic relationship behavior.

Families of preschoolers participated in two dyadic home visits, once with mother (56 dyads) and once with father (59 dyads). Each member of the dyad provided three cortisol samples and participated in several interaction tasks that were behaviorally coded. Approximately half of the children had been diagnosed with autism spectrum disorders (ASD), whereas half were typically developing (TD). In a multilevel model, father's cortisol level at each timepoint predicted child cortisol. Father-child linkage was stronger in dyads that showed less reciprocity, in which fathers showed less sensitivity, and in which children showed less self-regulation and more withdrawal. Cortisol levels were not significantly correlated in mother-child dyads, and there was a trend toward moderation by ASD diagnosis, such that linkage was greater in TD children. Mother-child linkage was stronger in dyads that showed less behavioral coordination and less sensitivity. HPA axis linkage may be stronger in less behaviorally attuned dyads.