Bullying Victimization Heightens Cortisol Response to Psychosocial Stress in Chinese Children

Childhood adverse experiences have been consistently documented to engender persistent changes in the hypothalamic-pituitary-adrenal (HPA) axis reactivity to chronic stress. However, there has been very little research examining whether this effect can be elicited among children when using a standardized laboratory stress test, or whether such effects are found in non-Western youth. In the current study, 80 10-year-old Chinese children (45% girls, 4-5th grades) were selected from 970 students based on the experience of being bullied, resulting in a sample of 59 victims (physical, verbal, and relational/social), and a group of 21 nonbullied children with distributions of age and gender that were comparable. We examined the association between bullying victimization and cortisol reactivity to the Trier Social Stress Test (TSST) at six time points using repeated-measures analyses of variance. The results showed that the TSST was a valid protocol among Chinese children for testing the functioning of HPA axis, based on two indicators: cortisol increase in response to stressor, and cortisol decrease after stressor removal. Based on the TSST, both cortisol reactivity and total cortisol concentration over the course of TSST were higher in bullied children relative to nonbullied children. Moreover, there were no differences in cortisol levels between victimization sub-types. Our study extended prior findings, by showing that cortisol dysregulation in response to stress may be related to bullying victimization.