The within-person coordination of HPA and ANS activity in stress response: Relation with behavior problems

This study tests the within-person coordination of HPA and ANS activity in response to stress and examines for the first time the association between such coordination and behavior problems in minority urban children. Participants, ages 11-12 (N = 419; 50 % male; 80 % African American) completed the Youth Self Report for externalizing and internalizing problems and a modified Trier Social Stress Task (mTSST). They also provided saliva samples for cortisol and alpha-amylase (AA) prior to and 5, 20 and 40 min post-mTSST. Analyses revealed a positive cortisol-sAA coordination, with a 1% increase in cortisol corresponding to a 0.20 % average increase in sAA in response to stress. Higher degrees of within-person cortisol-sAA coordination predicted more behavior problems. The cortisol-sAA coordination explained 28 % and 10 % of the variance in externalizing and internalizing problems, much larger than when stress dynamics of single systems or the interaction of cortisol (AUCi) and sAA (AUCi) were predictors. Findings highlight the importance of multisystem interplay in stress responding in understanding behavior problems. Individuals with more behavior problems may have difficulty turning off their "fight or flight" ANS response, with this system remaining active to the stimulating influence of cortisol even when cortisol's stimulating effects should have dissipated.