Neuroendocrine Aspects of Primary Endogenous Depression

To examine both predexamethasone and postdexamethasone cortisol measures in depression, we determined circadian serum cortisol patterns, cortisol responses to dexamethasone, and 24-hour urinary free cortisol excretion before and after dexamethasone administration in 40 patients with primary, definite endogenous depression diagnosed by Research Diagnostic Criteria and in 40 individually matched normal control subjects. Fifteen patients (38%) were dexamethasone nonsuppressors; they had significantly higher predexamethasone serum and urine cortisol measures than both their matched controls and the 25 suppressor patients. Both the predexamethasone and postdexamethasone cortisol measures were unimodally distributed across the patients and the controls. Circadian cortisol rhythms of similar magnitude occurred in both groups. The cortisol measures before and after dexamethasone administration were positively correlated to a similar degree in the patients and their controls, suggesting that predexamethasone hypothalamic-pituitary-adrenocortical hyperactivity and postdexamethasone cortisol nonsuppression are not independently determined in endogenous depression.