ATLANTA--Individuals with major depression have an exaggerated inflammatory response to psychological stress compared to those who do not suffer from depression, according to a study by researchers at Emory University School of Medicine. Because an overactive inflammatory response may contribute to a number of medical disorders as well as to depression, the findings suggest that increased inflammatory responses to stress in depressed patients may be a link between depression and other diseases, including heart disease, as well as contributing to depression itself.
Results of the study, led by Andrew Miller, MD, and Christine Heim, PhD, of Emory's Department of Psychiatry and Behavioral Sciences, are published in the Sept. 1 issue of the American Journal of Psychiatry.
"Several examples of increased resting inflammation in depressed patients already exist in the literature, but this is the first time anyone has shown evidence to suggest that the inflammatory response to stress may be greater in depressed people," says Dr. Miller.
The study included 28 medically healthy male participants, half of whom were diagnosed with major depression and half of whom were not depressed. The participants were exposed to two moderately stressful situations during a 20-minute time period. Blood was collected every 15 minutes starting immediately before and then up to an hour and a half after the test to check for key indicators of inflammation. The researchers measured levels of a pro-inflammatory cytokine (a regulatory protein secreted by the immune system) called interleukin-6, and the activity of a pro-inflammatory signaling molecule in white blood cells called nuclear factor-kB.
While at rest (before the stress challenge), the depressed patients had increased inflammation relative to the control group. Both the depressed and the healthy groups showed an inflammatory response to the stress challenge, but people who were currently d
Contact: Kathi Baker
Emory University Health Sciences Center