CRH and major depressive disorder: Studies demonstrated elevated levels of cortisol in plasma, CSF, and 24-h urine samples, high CSF corticotrophin releasing hormone (CRH) levels, blunted responses to CRH administration, and non-suppression of cortisol secretion on the dexamethasone suppression test in MDD (Carroll et al., 1976, 1981; Jarrett et al., 1983; Nemeroff et al., 1984; Halbreich et al., 1985; Holsboer et al., 1985; Banki et al., 1987; Evans and Nemeroff, 1987; Rubin et al., 1987; Heim et al., 2001; Newport et al., 2003; Raison and Miller, 2003).