Abstract:Adrenocortical stimulation with ACTH both in the morning (M‐test) and in the evening (Etest) and the dexamethasone suppression test were carried out in patients suffering from endogenous depression (DEP) and normal controls (NOR). A greater cortisol release in DEP was recognized than in NOR in the M‐test, an earlier peak response of DEP was shown in the M‐test than in the Etest, and a lack of association between hypersecretion of cortisol during depression and cortisol output after ACTH administration was noted. These findings, together with the results of DST, suggest that excessive activity of the hypothalamic‐pituitary‐adrenal (HPA) axis in depression may result, partly, from adrenocortical hyperrespo