Background: There is evidence that treatment with the 11 beta-hydroxylase inhibitor metyrapone may represent an alternative treatment strategy in major depression, As a consequence of inhibition of cortisol synthesis the overdrive of corticotropin leads to an accumulation of precursor steroids. However, the effects of metyrapone on the concentrations of endogenous neuroactive steroids that modulate ion channels, e.g., the GABA(A) receptor, have not vet been studied systematically. Methods: Therefore, we quantified the concentrations of an array of neuroactive steroids following administration of 1.5g metyrapone before and after pretreatment with I mg dexamethasone in 19 patients suffering from severe depression in comparison to 13 healthy c...