The connecting between stress, depression and anxiety has been known for a long time. Of course, stress has a negative impact us emotionally. Stress also has a physiological effect on the body, causing hormonal and inflammatory changes that can lead to the development of depression and anxiety.
Releases of Cortisol
A stressful event causes the release of cortisol, the stress hormone, from the adrenal glands. This reaction involves both the nervous system and the endocrine system, and affects the whole body.
A stressful event causes a part of the brain called the hippocampus to secrete corticotrophin releasing hormone (CRT) which then stimulates the pituitary gland to create ACTH or corticotrophin. ACTH travels through the blood stream and acts on the adrenal glands to cause the release of cortisol and other hormones.
The cortisol then circulates throughout the body, affecting every organ, priming them for extra metabolic activity. This is often referred to as the flight or flight response.
A negative feedback loop stops the release of cortisol from the adrenal glands. The circulating cortisol in the blood stream will bind to receptors in the brain, called glucocorticoid receptors (GR) and to stop the further production of CRT.
Stress and Inflammation
A problem in the negative feedback loop can occur from chronic stress. This deals with the effect excess stress has on the hormonal feedback receptors.
Excessive cortisol causes the GR receptors to become less sensitive to the hormone, so it is more difficult to turn off the negative feedback loop and allows cortisol production to become excessive. As a result of the excess cortisol in blood circulation and the excess stimulation of the hippocampus, the sympathetic nervous system (fight or flight response) remains activated 1. Eventually this causes cells in the immune system to release proinflammtory cytokines, which are molecules that promote inflammation.
The proinflammatory cytokines may inhibit cellular repair of the nervous system, leading to neuronal cell death and damage. It may also disrupt the normal functioning of neurotransmitters 1. In addition, alterations in the GR may lead to changes in gene expression, further reducing the ability of the brain to repair itself 2.
Is depression just physical?
No, one cannot say from this work that depression is only physical. This theory argues that the damage to the cells and chronic inflammation may further exacerbate the impact of stress on your mind and emotions making it easier to become more depressed and harder to treat it 3. But it can also shed light on how we can improve our treatments.
In the next post, I will discuss how acupuncture can help treat depression, control the impact of stress, and reduce inflammation.
If you are currently need emergency mental health you can call 1800-273-TALK.
Photos: The Rocketeer