e-pearls newsletter, March 2009:
There has been increasing evidence over the years showing a strong association between psychological stress, depression, and physical illness. This rather direct link has been well-established in the literature; this month’s focus is on the relationship between stress and heart disease, which is just one aspect of the so-called mind-body connection.
As counselors, we are in an excellent position to help our clients deal with stress. By so doing, we may be helping them not only from a psychological standpoint, but from a physical one as well. I have been fascinated by the relationship between the mind and body for a long time; look for more on this in future editions!
Background
When subjected to psychological (or physical) stress, there is a rise in serum cortisol and adrenaline, which are produced by the adrenal gland. Both of these are so-called “stress hormones;” taken together, they cause an increase in heart rate, blood pressure, and blood glucose. This essentially gets us “primed” to act quickly in response to a given situation. Cortisol also stimulates the immune system to manufacture small proteins called pro-inflammatory cytokines, which serve to increase inflammation in the body.
These same cytokines also trigger a key enzyme that breaks down tryptophan, an amino acid that is necessary for the manufacture of serotonin. The result is a depletion of serotonin, often leading to the development of depression. Because these cytokines also promote inflammation, they may lead to an increased risk of many inflammatory diseases such as diabetes and arthritis (among others) as well as coronary heart disease.
Chronic Stress, Depression, and Coronary Heart Disease (CHD)
Before getting much further, it is necessary to define a few terms here. “Coronary heart disease,” or CHD, refers to heart disease related to narrowing of the arteries that supply blood to the heart, namely the coronary arteries. When far enough advanced, CHD results in a heart attack because the heart muscle cells are deprived of oxygen and other nutrients.
This narrowing of the coronary arteries often involves so-called “plaque,” which is the build-up of cholesterol (and sometimes calcium as well) in the wall of the artery, causing it to become narrowed (think of a pipe with a glob of gunk stuck on the inside; you get the picture). Anyway, there’s lots of evidence in the literature that these plaques often become inflamed, causing them to become fragile and prone to breakage. When that happens, this “gunk” breaks off and may completely block the artery.
This is what happens in a heart attack. The thinking is that chronic psychological stress causes increased cytokine production by the immune system, resulting not only in depression, but also in an ongoing inflammatory process that in this case involves the coronary arteries. In fact, depression is a major risk factor for CHD, right up there along with smoking, high blood pressure, and diabetes.
Sudden Psychological Stress and the Sympathetic Nervous System
In addition to the release of cortisol and the subsequent rise in blood levels of cytokines, adrenaline is also released by the adrenal gland in response to a sudden emotional stress. Adrenaline causes something called the sympathetic nervous system (which is part of the nervous system that controls heart rate and blood pressure) to become activated. When this happens, heart rate and blood pressure rise. Usually this is transient, and does not result in any physical impairment.
However, in some cases, actual physical changes can take place. For instance, there have been reports of sudden enlargement of the heart (“congestive heart failure,” in medical lingo) with the resulting buildup of fluid in the lungs (“pulmonary edema”) in response to receiving the unexpected news of the death of a loved one. Granted, this is rare, but nonetheless is a powerful example of just how intimately the mind and body are connected.
Panic Disorder and Cardiac Risk
People who suffer from panic disorder often experience cardiac symptoms such as chest pain or a sensation of a rapid heartbeat. Medical testing usually reveals no abnormality, and patients are typically reassured that there is no risk of physical harm.
However, this turns out not to be the case. There is in fact an increased risk of sudden death from heart attack and/or heart rhythm disturbances during panic attacks. This is caused by the sudden increase of sympathetic nervous system activity discussed above, which in this case causes spasm of the coronary arteries (resulting in severe narrowing) and/or an irregular heart beat (causing a fatal drop in blood pressure). This can happen even in people who have no known history of cardiac disease, and serves as yet another example of how powerful the mind-body connection can be.
References
Anda, R., et al. (1993). Depressed affect, hopelessness, and the risk of ischemic heart disease in a cohort of U.S. adults. Epidemiology, 4, 285-294.
Esler, M., Schwarz, R., Alvarenga, M. (2008). Mental stress is a cause of cardiovascular diseases: From scepticism to certainty. Stress and Health, 24, 175-180.
Maes, M., et al. (1997). Serotonin-immune interactions in major depression: Lower serum tryptophan as a marker of an immune-inflammatory response. European Archives of Psychiatry and Clinical Neuroscience, 247, 154-161.
Wellen, K.E., Hotamisligil, G.S. (2005). Inflammation, stress, and diabetes. The Journal of Clinical Investigation, 115, 1111-1119.
Wittstein, I.S., et al. (2005). Neurohumoral features of myocardial stunning due to sudden emotional stress. The New England Journal of Medicine, 352, 539-548.
