Moreover, significant differences in ACTH response to CRH and AVP tests were found in nonhuman primates differing in stress behavior, with a higher rise in ACTH secretion in individuals with anxiety and depression-like behavior, similar to intergroup differences in ACTH response to ASE in old female rhesus monkeys, and in contrast to the absence of between-group differences in ACTH response to ASE in young monkeys (6, 61). Here, POMC is linked to major depressive disorder.