Depression is considered to increase the risk of heart disease. This has been known for some time, but the actual process that links depression to heart disease is less clear. New research, published in the Journal of the American Medical Association, suggests that depression contributes to heart disease indirectly, and mainly through negative changes in health behaviors.
There are essentially two paths that link psychological issues with physical diseases. The first is a direct path, but one that is actually very difficult to prove. There are very many physical examples of a direct path (e.g. coming into contact with an allergen causes an allergic reaction) but attempts to forge a direct link between psychological problems and physical diseases are more complex. For this reason, researchers tend to explore more indirect routes. So, in the case of depression and heart disease, it is possible to see how depression is associated with lack of motivation, which reduces physical activity, which leads to increased weight, and so on.
In this most recent study, Dr. Mary A. Wooley, of the VA Medical Center in San Francisco, followed the medical progress of over one thousand patients with heart disease, for nearly five years. Patients completed a questionnaire to establish whether they had depressive symptoms. Wooley then compared the depressed group with the others in the sample and found that those with depression were less likely to follow their prescribed treatment, were more likely to smoke and less likely to be physically active.
During the period of research a number of blood and urine samples were taken in order to evaluate possible changes in factors known to have a bearing on heart disease. This included serotonin and norepinephrine levels, cortisol, omega-3 fatty acids and the inflammatory marker C-reactive protein.
Researchers also concentrated on the depressed group and adjusted for issues that could account for a cardiac event. Even so, the group with depression was still 31 percent more likely to have a cardiac event. The research team then calculated that physical inactivity was associated with a 44 percent greater rate of cardiovascular events.
According to the research team, the results provide further proof that heart problems associated with depression, could be prevented by simple modifications to lifestyle. As to whether depression or heart disease comes first, Dr. Wooley says it really doesn't matter. What really matters is tackling the behaviors that seem to link depression with heart disease. So this means a more active lifestyle, better diet and stopping smoking.