In a review of the scientific literature on the relationship between stress and disease, Carnegie Mellon University psychologist Sheldon Cohen has found that stress is a contributing factor in human disease, and in particular depression, cardiovascular disease and HIV/AIDS.
Cohen's findings will be published in the Oct. 10 issue of the Journal of the American Medical Association (JAMA). The article was co-authored by Denise Janicki-Deverts of Carnegie Mellon and Gregory E. Miller of the University of British Columbia.
Cohen's JAMA article was based on a paper commissioned by the Institute of Medicine to examine the evidence that stress influences major diseases. In the JAMA article, the authors consider the behavioral and biological mechanisms through which stress contributes to disease and weigh the results of studies that have examined whether stress plays a role in depression, cardiovascular disease, HIV/AIDS and cancer. Those studies reveal that stress plays a role in triggering or worsening depression and cardiovascular disease and in speeding the progression of HIV/AIDS.
“The majority of people confronted with even traumatic events remain disease-free. Stress increases your risk of developing disease, but it doesn't mean that just because you are exposed to stressful events, you are going to get sick,” said Cohen, the Robert E. Doherty Professor of Psychology at Carnegie Mellon.
According to the authors, the strongest evidence that stress contributes to disease comes from research on depression, which shows that stress is associated with the onset of depression as well as relapse in people who have recovered from it. Cohen said that particular types of stress are the biggest culprits in depression, namely “social stressors” such as divorce and the death of a loved one. Depression also is common among people who have been diagnosed with a serious illness, suggesting that physical disease itself is a stressful event that can lead to depression. On the other hand, chronic stress -- such as stress experienced daily in the workplace -- contributes to cardiovascular illnesses such as coronary heart disease, a relationship that medical studies have clearly demonstrated, Cohen said.
Results of research on the relationship between stress and HIV/AIDS have been less clear, but since 2000 studies have consistently demonstrated a link between stress and the progression of AIDS. Cohen said that the impact of stress may have become more pronounced in recent years because of the complex and demanding drug regimen that AIDS patients now undergo. He said stress may tax their ability to keep up with their treatment. In the JAMA paper, the authors also note that changes in the autonomic nervous system caused by stress may also contribute to disease progression by influencing the replication of the HIV virus.