It's well-known that chronic stress takes a physical and emotional toll. But new research may provide some hints as to why.

It appears chronic stress shortens immune cell telomeres-DNA-protein complexes at the ends of chromosomes that promote genetic stability-impairing their ability to divide and multiply. This process may hinder the body's ability to fight off infection and cause premature onset of diseases, according to a study by Elissa S. Epel, PhD,an assistant psychiatry professor at the University of California, San Francisco.

In contrast, research with rats and mice shows that short-term stress may actually benefit the body by revving up the immune system. That's according to work by Firdaus Dhabhar, PhD, associate professor of psychiatry and behavioral sciences at Stanford University.

The two will discuss their new findings on stress's cellular effects at the APA Annual Convention symposium "Stress and Health Revisited," on Saturday, Aug. 18, at 1 p.m. The Board of Scientific Affairs Committee on Animal Research and Ethics-sponsored session will explore these researchers' contributions to the emerging field of psychoneuroimmunology, or PNI, which explores connections between the brain and immune system.

"We're starting to be able to identify the molecular and cellular mechanisms whereby psychological stress is translated into a compromised health status," says Mary Meagher, PhD, a psychology professor at Texas A&M University and chair of the session.

The presenters will also discuss how PNI research may be translated into clinical applications.

-A. Cynkar