Glucocorticoid Sensitivity in Mood Disorders

In this review, we provide an overview of recent literature on glucocorticoid (GC) sensitivity in mood disorders. Assessing GC sensitivity is often performed by measuring the cortisol awakening rise (CAR), by challenging the hypothalamic-pituitary-adrenal (HPA) axis using a dexamethasone suppression test (DST) or a dexamethasone/cortisol-releasing hormone test (DEX/CRH); more recently by measuring cortisol as a retrospective calendar in scalp hair. The main findings in mood disorders are higher mean cortisol levels in hair samples and a higher CAR, showing a hyperactivity of the HPA axis. This is in line with the mild resistance for GCs previously observed in challenge tests during mood episodes. GC sensitivity is partly determined by polymorphisms in the genes encoding receptors and other proteins involved in the regulation of the HPA axis. We shortly discuss the glucocorticoid receptor, as well as the mineralocorticoid receptor, the cortisol-releasing hormone receptor-1, and the glucocorticoid receptor co-chaperone FKBP5. Data clearly indicate genetic changes, along with epigenetic changes which influence the set-point and regulation of the HPA axis. Early trauma, as well as influences in utero, appears to be important. Future research is necessary to further clarify the biological background and consequences of an individual's cortisol exposure in relation to mood.