Individual differences in cortisol responses to fear and frustration in middle childhood

摘要

The purpose of this study was to examine individual differences in the activation and regulation of the Hypothalamic-Pituitary-Adrenal (HPA) Axis in pre-pubertal children after exposure to two different stress modalities, and to evaluate the utility of an individual differences approach to the examination of HPA-axis functioning. After a 30 minute controlled baseline period, 73 seven-year-old children (40 males and 33 females) were randomly assigned to a validity check condition, or one of two experimental tasks designed to elicit fear or frustration. This was followed by a 60-minute controlled regulation phase. A total of 17 saliva samples were collected, including 12 post-stress samples at 5-minute intervals. There was a significant stress modality effect, with children exposed to the fear condition reaching peak cortisol levels at 25 minutes post-stress, while those exposed to the frustration condition reached peak levels at 45 minutes post-stress. There was no difference in peak cortisol levels between the stress modalities. Individual variability across conditions was significant with subjects reaching peak levels as early as 10 minutes post-stress and as late as 60 minutes post-stress. Our data suggest that analysis of individual curves prior to making group level comparisons may improve the explanatory power of HPA-axis-behavior models.