Daily parent-adolescent cortisol associations: Unpacking the direction of effects.

Prior studies suggest bidirectional relationships between parent and adolescent behavior. This study examined how parents and their adolescent child's cortisol patterns are associated across days and if there are bidirectional associations between parent and child cortisol. Participants included two samples of employees and their children who participated in a daily diary study where diurnal salivary cortisol was collected on four study days (N = 318 dyads, Myouth age = 13.18 years, 52 % female). Autoregressive cross-lagged models were used to estimate parent-driven effects (parent cortisol effects on adolescent cortisol) and adolescent-driven effects (adolescent cortisol effects on parent cortisol). Adolescents' steeper cortisol awakening response (CAR) was significantly associated with parents' steeper CAR the following day. Adolescents' higher bedtime cortisol levels were also significantly associated with parents' higher bedtime cortisol levels the following day. Parents' cortisol did not predict their children's next-day cortisol. Results support a primarily adolescent-driven process of stress transmission in families. These results suggest that interventions to reduce adolescent stress, as well as to reduce parents' reactivity to adolescents, may be warranted.