Stress Contributes To Range Of Chronic Diseases, Review Shows
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.
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.
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
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 otherhand, 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.
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.
differ with regard to rate of progression through the successive phases
of HIV infection. Some remain asymptomatic for extended periods and
respond well to medical treatment, whereas others progress rapidly to
AIDS onset, and suffer numerous complications and opportunistic
infections. Stress may account for some of this variability in HIV
progression," the authors write.
stress causes and contributes to disease is a question of particular
interest to researchers. Cohen said there are two likely pathways. One
is behavioral -- people under stress sleep poorly and are less likely
to exercise; they adopt poor eating habits, smoke more and don't comply
with medical treatment. Stress also triggers a response by the body's
endocrine systems, which release hormones that influence multiple other
biological systems, including the immune system.
stress on regulation of immune and inflammatory processes have the
potential to influence depression, infectious, autoimmune, and coronary
artery disease, and at least some (e.g., viral) cancers," the authors
the role of stress in cancer have not been consistent in their results.
Researchers who study the influence of stress on the progression of
cancer face many hurdles, according to Cohen and his colleagues. Cancer
can go undiagnosed for a long time, and its progression is difficult to
measure with much precision. There are many types of cancers, and it is
possible that stress only influences those facilitated by sustained
hormonal response and impairments in immunity.
"We will need
additional studies across a broader range of cancers before we can
fairly evaluate the role of stress in cancer," Cohen said.
For more information on Carnegie Mellon University, visit www.cmu.edu.