POMC and major depressive disorder: There seems to be differences in salivary cortisol between patients with endogenous and nonendogenous depression (Iorgulescu, 2006) generally, there is a correlation between plasma ACTH levels and salivary cortisol, but this relationship is not present in patients with endogenous depression, suggesting either an effect of medication or a disorder of regulation of cortisol secretion (Galard and others, 1991).