Stress Can Increase Disease Susceptibility.

• Position: Brief Article

Researchers who have spent years studying the effects of stress on the body's immune system now believe they know enough to demonstrate that it actually does weaken a person's health. Dozens of studies have shown that stress can alter the levels of certain biochemical markers in the body--key players in the human immune response--but scientists weren't sure those changes actually led to poorer health. Today, they seem convinced.

A team of researchers from five universities maintain that stress can lessen people's immune response and that change can make them more susceptible to infectious diseases. They also say that increased stress may lessen the effectiveness of certain vaccines and can confound some studies of certain illnesses that affect the immune system, such as autoimmune diseases and AIDS.

"The evidence so far suggests that, while the immune changes associated with psychological stress are generally small, they look like they're important enough to have biological consequences and increase health risks," explains Ronald Glaser, professor of medical microbiology and immunology at Ohio State University, Columbus, and lead author of the study.

The researchers point to the important role that compounds known as cytokines play in regulating the immune response. In some cases, they stimulate the release of other compounds essential for inflammation. In others, they...