Abstract
An accumulating body of literature has shown a link between early pubertal maturation and internalizing problems, particularly among girls. Our knowledge is, however, limited with regard to what accounts for this association. Based on a hypothesis that early maturing girls have heightened stress sensitivity that increases the risk of internalizing problems, the present investigation examined the roles of pubertal timing and salivary cortisol reactivity to interpersonal stressors in adolescents' internalizing problems. Results from 110 boys and 106 girls (ages 11-16) indicated that early maturing adolescents had increased internalizing symptoms. Early maturing girls' higher levels of internalizing problems were at least partially attributed to their heightened sensitivity to interpersonal stress. Finally, girls' cortisol reactivity to interpersonal challenge was more strongly associated with internalizing problems than boys' reactivity.