The HPA axis

Professor James Potash explains that the HPA (hypothalamic pituitary adrenal) axis is the system that control the stress response. The hormone cortisol is intrinsic to this system.

The HPA axis, or the hypothalamic-pituitary-adrenal axis, is the system that controls the stress response. It has been clear for many years, in fact going back to the late 1950s, there have been studies demonstrating abnormalities in that system in depression. In particular, people with depression have elevated rates of the stress hormone cortisol, which is produced by the adrenal gland (part of the HPA axis). There has been a question as to whether the elevated cortisol is “chicken or egg” – is it the elevation of cortisol in response to stressors that causes depression, or is depression itself a stressful experience that leads to increases in cortisol? The answer probably is some of each it would appear right now. There are people working on medications to block that increase in cortisol as a potential treatment for depression.