Electronic Thesis and Dissertation Repository


Master of Science




Hayden, Elizabeth P.


Females’ reactivity to stress appears to be closely tied to internalizing symptoms, while males who are under-reactive may be at risk for externalizing problems. Little is known about when such differences emerge, despite possible implications for early prevention. Cortisol reactivity to a laboratory stressor was assessed in 409 three-year-old children along with children’s parent-reported internalizing and externalizing symptoms, which were re-collected at child ages 5 and 8. Multilevel modelling was used to investigate whether the relationship between cortisol reactivity and symptoms differed between boys and girls longitudinally. Over time, girls with lower cortisol reactivity showed a decrease in depressive symptoms while girls with higher reactivity showed relatively elevated symptoms. Boys with higher cortisol reactivity showed a decrease in externalizing problems; boys with lower reactivity remained relatively stable in such symptoms. Findings suggest sex differences in children’s stress reactivity, with implications for the later manifestation of symptoms across childhood.