Evidence in support of decreased glucocorticoid sensitivity, commonly referred to as GR, in depressed patients arises from studies assessing GR response to the synthetic glucocorticoid dexamethasone and the dexamethasone-CRH stimulation test with studies repeatedly reporting impaired glucocorticoid responsiveness and nonsuppression of cortisol secretion, which has been shown to correlate with depression severity and age (Carroll et al., 1981; von Bardeleben and Holsboer, 1991; Holsboer, 2000; Pariante and Miller, 2001; Ising et al., 2007). This evidence concerns the gene NR3C1 and major depressive disorder.