The neuroendocrinology of depression

Recent studies on the relationship between depression and the hypothalamic pituitary adrenal axis are of general interest from three points of view. Firstly, exactly the same adaptive changes are seen in depressed patients as in animals exposed to chronic stress: in both there is an increased central activation of the axis impaired negative feedback control and adrenal hypertrophy. The second general conclusion is that the environmental stressors which predispose towards depression in man also activate the HPA axis in animals and possibly in man as well. This suggests that activation of the HPA axis is a useful marker of environmental predisposition towards depression. The third general conclusion is that HPA activation may be a mediator as well as a marker of the environmental influence on depression. This is both for animal models of depression and for clinical depression which may be amenable to treatment with drugs which inhibit the synthesis of cortisol.