Extraversion Mediates the Effects of Early Childhood Trauma on the Cortisol Awakening Response

Early exposures to traumatic experiences have been implicated in both negative psychological and physical health outcomes in adults, but recent studies have shown that an extraverted personality can buffer those effects. In recent years, attention has turned to the hypothalamic-pituitary-adrenal axis (HPA axis) and more specifically alterations of the cortisol awakening response (CAR) as a biomarker of negative health outcomes. While studies have looked at the CAR in the general population, there is insufficient research looking at the CAR in Mexican Americans. Mexican Americans now account for nearly two-thirds of the Hispanic population and are the largest immigrant group in the United States. There are also different risk factors that can increase early trauma exposure in Mexican Americans leaving them more susceptible to later negative health outcomes. The aim of this study is to examine the relationships between early trauma, extraversion, and the CAR in Mexican Americans. Seventy-one participants answered a litany of psychometric instruments and also provided salivary samples for analysis. Results showed that early trauma predicted a change in CAR, such that greater exposure to early trauma led to an attenuated delta CAR. Extraversion predicted a change in CAR, such that greater extraversion led to a more robust delta CAR. Early trauma was also shown to be inversely associated with extraversion, suggesting that early trauma may have an effect on personality formation. Finally, extraversion mediated the effects of early trauma on the delta CAR, suggesting that extraversion plays an important role in the regulation of the CAR.