Abstract

Previous investigations of the association between cortisol and physical and mental health outcomes have yielded inconsistent results. Examining how long the individual has experienced the problem may help clarify these divergent findings. Four questions were examined including (1) Do the associations between diurnal cortisol and internalizing behaviours differ depending on how long youth have experienced the behaviours? (2) Do the associations between diurnal cortisol and externalizing behaviours differ depending on how long youth have experienced the behaviours? (3) Do associations persist if behaviours are examined at a later point in time (i.e. mid-adolescence)? (4) Do the associations between diurnal cortisol and physical health problems in early adolescence differ depending on the chronicity of the health problem?
Data from the Concordia Longitudinal Risk Project were employed to examine these associations. In general, results suggest that the association between cortisol and health outcomes differ depending on how long the problem has been experienced. When examined concurrently in adolescence, youth with more internalizing behaviours had higher morning cortisol; however, when examined longitudinally, youth with more internalizing behaviours in childhood had lower morning cortisol levels as adolescents. Youth with more externalizing behaviours in childhood had flattened diurnal cortisol rhythms as adolescents, and this finding
persisted when examined in adolescence. Similarly, blunted patterns of adrenocortical activity in early adolescence were also related to more internalizing and externalizing behaviours in mid-adolescence. Furthermore, this notion seems to hold true for physical health problems such that acute health problems (i.e. infections) were associated with elevated levels of cortisol whereas more chronic health problems (i.e. asthma and allergies) were associated with blunted patterns of diurnal cortisol. The findings suggest that both hyper- and hypocortisolism may be evident within the same sample and this is related to how long the problem had been experienced. Future research should consider sampling cortisol at more than one time point to more thoroughly examine the possibility of blunted hypothalamic-pituitary-adrenal axis activity in prospective, longitudinal studies.