Stress, Disease Likely Linked, Say Psychologists

In an Oct. 9 press release, a new commentary looks at the link between psychological stress and disease. The psychologist who wrote the commentary examined four diseases (depression, HIV/Aids, cancer and heart disease) and how much stress played a role in their development.

Sheldon Cohen, Ph.D., is a psychology professor at Carnegie Mellon University and the lead author of the commentary. He said that he and his colleagues found that the link between stress and depression and stress and heart disease were the most convincing. The stress and HIV/Aids link was somewhat less, and the role of stress in the development of cancer appeared very weak. Interestingly, animal studies of the relationship between stress and cancer were quite convincing that there is a link.

In multiple animal studies, experiments and laboratory studies of individuals exposed to brief, acute stress, researchers have been able to document changes in the way the body functions when stressed. However, since it would be unethical to expose a person to ongoing or long-term stress that could cause permanent harm, solid, irrefutable evidence from randomized experimental studies isn't available. Nonetheless, Cohen and his colleagues say the evidence they have available so far certainly adds up.

In the studies that have been done in cases where individuals were exposed to brief, acute stress, the researchers looked for the effect of that stress on body systems known to be related to disease, such as heart rate, blood pressure or changes in immune function.

In other stress level studies, the stress levels of the participants were measured. The participants were then followed to see if those who experienced the most stress were also the people who had the highest rates of death and disease. One problem with this approach, however, is that "there could be environmental or personality characteristics that influence both why a person is stressed and why they developed a disease," Cohen said.

In what can be termed natural experiments, researchers followed the health and death rates of people who experience stressors that are beyond their control, such as the death of someone close to them, a natural disaster or some other type of major loss or trauma. Since the subjects do not cause the stressful event, these studies are not subject to the alternative explanations that can be seen in other studies.

Researchers know that sustained stress can affect everything from metabolism to resting heart rate to the body's response to infection and inflammation. The commentary also states that stress may also increase the risk of disease because people under heavy stress tend to smoke more, sleep less, eat less healthy diets and exercise less.

In summation, Cohen said that "the existing evidence linking stress to health is impressive. What we need now is to find out what actually works to reduce stress. After that we'd like to see randomized controlled trials to determine if these stress-reducing strategies translate to less disease."

Source:

Press release, Researchers Say Stress and Disease Are Likely Linked; http://www.newswise.com/articles/view/534175/