Chronic stress can make you clinically depressed. Stress- either physical or emotional stress- produces a cascade of different hormonal changes in the body.
These hormones act in a feedback called the HPA (hypothalamic-pituitary-adrenal) axis. Stress prompts the release of CRF (cortisol releasing factor) from the hypothalamus. CRF alerts the pituitary gland to secrete ACTH (adrenocorticotrophin hormone).
Then ACTH tells the adrenals to produce more cortisol.
Like adrenalin, cortisol is an essential stress hormone without which we would not survive. However, too much of it can be damaging, especially to the heart, brain, muscles and organs.
Fortunately, cortisol inhibits further secretions of CRF and ACTH, thus completing the feedback loop and shutting down any excessive
secretions of CRF. These mechanisms are essential to stop the HPA axis from damaging the body. When something goes wrong, and the HPA axis secretes cortisol at dangerous levels, a whole plethora of familiar stress-induced diseases and mental complaints can arise.
The HPA axis drives the famous fight-flight response. Under threat, adrenalin rises, heart rate and blood pressure increases, and blood flows to the muscles for running and fighting.
However, when acute stress becomes chronic and long-term, then cortisol becomes the dominant hormone in positioning bodily functions to handle the stress. Many of the normal bodily processes shut down for the perceived continuing emergency: cell reproduction slows, organ function slows, the immune system becomes suppressed, sleep is more difficult, but appetite actually increases (this is why cortisol is linked to weight gain). Other effects include lowered sex drive, damage to brain areas including the hippocampus (where emotional memories are stored), distortion of neurochemical receptor sites (because cortisol, treduces expression of the gene that produces the 5-HT1A serotonin receptor), destruction of neurons, and damage to the heart.
The destructive consequences of prolonged exposure to cortisol have led some health researchers to speak of "cortisol poisoning". It is easy to see why roughly 50% of severely depressed patients who have been tested have elevated cortisol levels.
In addition, chronic severe stress in newborns can damage the HPA axis itself, and cause increased sensitivity to stress in later life. This is partially why children who have a traumatic childhood are more prone to anxiety and depression later on.
The HPA axis evolved to help people cope with physical stress. Unfortunately, the HPA axis is also stimulated by emotional stress. The more primitive areas of the brain have great difficulty distinguishing between an imagined threat, and a real one. That means that over time, worry can be as dangerous a stressor to your body as real physical danger.
When The HPA Axis Shifts Into Overdrive
Prolonged stress may help create abnormalities in the HPA axis that can lead to depression. These abnormalities include raised levels of CRF and cortisol, abnormalities of the cortisol receptors, causing the HPA feedback loop to be constantly overactive, even when excess cortisol should shut down secretions.
How does cortisol cause depression? Unremitting stress causes a continual release of cortisol that can transform anxiety into depression by depleting levels of dopamine. This denies dopamine to the pleasure circuitry of the prefrontal cortex, as well as other pleasure pathways, literally preventing the sufferer from feeling good.
The increased cortisol acts like an steroid bombardment on neurotransmitters involved in depression, influencing both the formation and breakdown of serotonin and noradrenaline (which are the targets of modern antidepressant drugs such as selective serotonin reuptake inhibitors). At the same time cortisol may disrupt the receptor sites for these neurochemicals. These are the likely mechanisms of cortisol's contribution to depression.
SSRIs (selective serotonin reuptake inhibitors) have been shown to reverse the damage done to the HPA axis, and to reduce damage to the hippocampus done by excessive cortisol. This is another example of the interrelationship of stress, the HPA axis, and depression.
Psychologists have long understood that severe chronic stress can cause depression. Genetic predispositions to stress related depression are probably common. Unfortunately, depression, even when caused by other means, is a major psychological stressor that can also active the HPA axis and release cortisol, which may further contribute to depression.
In short: stress, anxiety, and depression can exist in a feedback loop that contribute to the further degeneration of these conditions. By the same logic, many treatments that interrupt the HPA axis and lower cortsiol have the potential for alleviating both stress/anxiety and depression.
If you are concerned about your cortisol levels, then you should find a good endocrinologist, in order to receive specialized and complex
endocrine tests. The American Association of Clinical Endocrinologists has an online listing of member endocrinologists.
Not surprisingly, pharmaceutical companies are currently developing a new generation of drugs which will inhibit the overactivity of the HPA axis.
If Your HPA Axis is In Overdrive, How Can You Slow the Production Of Cortisol?
Many stress reduction methods, from acupuncture to aerobics to cognitive behavioral therapy, have been shown to inhibit overactivity in the HPA axis, and lower cortisol. Even massage or meditation can lower cortisol.
You could also try increasing your DHEA hormone levels, which helps to buffer the body against any excess effects of cortisol and relieve depressive symptoms. DHEA is available in many health food stores.
Unfortunately DHEA is a testosterone precursor, so DHEA can be a problem for some people, and may at least cause facial hair growth in women and sometimes acne. DHEA use should be monitored by a physician. Some M.Ds. who work with DHEA recommend taking only lower dosages, not more than 5mg. Some supplement companies sell a metabolite of DHEA called 7-Keto, which is reported to not break down into testosterone in the bloodstream the way DHEA does.
Other natural approaches that lower cortisol include:
One caution: exercise is a superb proven treatment for depression. However, don't be so vigorous that you stress the body excessively, and thus contribute to your cortisol induced depression. If it hurts, don't do it.
Remember, not all depression is stress-related. The alternative solutions on this site have been chosen for their ability to decrease stress-related anxiety and depression as well as other form of these disorders.
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