The oCRH stimulation test before and after clinical recovery from depression

A substantial body of data suggests that excessive cortisol secretion in depression may result from a dysregulation at several sites within the hypothalamic-pituitary-adrenocortical (HPA) axis. These alterations in regulatory mechanisms are thought to be the result of a hypothalamic 'overdrive' of corticotropin-releasing hormone (CRH). Previous studies have demonstrated a diminished adrenocorticotropin (ACTH) secretory response, as well as a heightened adrenocortical responsiveness after ovine-CRH administration in depressed patients. In the present investigation, we examined pituitary and adrenocortical responsiveness after an ovine-CRH stimulation test before and during clinical recovery in seven depressed patients. Cumulative ACTH responses increased significantly during clinical recovery (P = 0.014). Paradoxically, maximum and peak cortisol responses increased after recovery, suggesting that heightened adrenocortical responsiveness to ACTH during depression may take longer to 'normalize' than abnormal pituitary responsiveness to ovine-CRH stimulation.