Mean 14.00-17.00 h plasma cortisol concentration and its relationship to the 1 mg-dexamethasone suppression response in depressives and controls.

Three-hour cortisol-profiles and cortisol responses to a 1 mg dose of dexamethasone were recorded in 31 depressed patients and nine controls. The data indicate that the likelihood of detecting non-suppressible cortisol concentrations after dexamethasone is significantly increased in depressed patients with a hypersecretion of cortisol. However, a considerable subsample of normosecretors shows abnormal DST results. Conversely, hypersecretion is often associated with dexamethasone suppression. In this study a 1 mg-DST did not reflect the adrenocortical activity with ultimate accuracy. Therefore any attempts which correlate psychopathological or biological data with pituitary-adrenal activity and use a DST-result as measure are criticizable . Data derived from volunteers illustrate that medical factors such as weight-loss, steroid-containing contraceptives and sleep deprivation can make a pituitary-adrenal activity test ambiguous.