The clearest example of this increased incidence is major depression. Prior to the onset of puberty, males and females have approximately equal rates of depression at 5%. With the onset of puberty, rates in females double, while males stay approximately the same (Angold, Costello, & Worthman, 1998). Many factors may play a role in this pattern, including different stresses associated with gender expectations, the higher incidence of exposure to trauma in young females, and differences in social cognitive function such as rejection sensitivity (Cyranowski et al., 2000; Zahn-Waxler & Shirtcliff, 2006). One potential mechanism is sex differences in the development of the HPA axis. Studies indicate that the increase in incidence of depression is linked to pubertal maturation rather than increases in chronological age (Angold et al., 1998). In females, there is an increased response of the HPA axis to stress with advancing puberty, while in males, the response is decreased, possibly associated with increased testosterone levels (Mccormick & Mathews, 2007).
