November 3, 2002

Chronic Stress Can Interfere with Normal Function of the Immune System, Suggests New Research

May increase susceptibility to inflammatory diseases such as allergic, autoimmune or cardiovascular diseases

WASHINGTON - Chronic stress not only makes people more vulnerable to catching illnesses but can also impair their immune system's ability to respond to its own anti-inflammatory signals that are triggered by certain hormones, say researchers, possibly altering the course of an inflammatory disease. This finding is reported on in the November issue of Health Psychology, published by the American Psychological Association (APA).

Chronic stress seems to impair the immune system's capacity to respond to glucocorticoid hormones that normally are responsible for terminating an inflammatory response following infection and/or injury, according to researchers Gregory E. Miller, Ph.D., of Washington University at St. Louis and colleagues. To examine what happens to people's immune systems during on-going stressful situations, the researchers compared 25 healthy parents with children undergoing treatment for pediatric cancer with 25 healthy parents with healthy children on measures of mental health, effects of social support and certain immune system responses. All the parents had blood drawn at the initial session and salivary cortisol samples taken at intermittent times over two days.

Parents of cancer parents reported more psychological distress than parents with healthy children, according to the study. The parents of cancer patients also were found to have diminished glucocorticoid sensitivity compared to parents of medically healthy children. This hormone is responsible for turning off the in vitro production of the pro-inflammatory cytokines interleukin-1B, interleukin-6 and tumor necrosis factor, said Dr. Miller. The good news found by the researchers was that social support lessened the immunologic consequences of caring for a child with cancer, perhaps by helping the parents deal with the economic, work and family disruptions caused by the disease and its treatment.

"These findings suggest a novel mechanism through which psychological stress could influence the onset and/or progression of conditions that involve excessive inflammation, like allergic, autoimmune, cardiovascular, infectious and rheumatologic illnesses," Dr. Miller. But even though the cancer patient parents reported more depressive symptoms, depression does not seem to operate as a mediator. It may be that anxiety, intrusive thoughts, feelings of helplessness or lack of sleep may be influencing the stress-related reductions in glucocorticoid sensitivity.

Article: "Chronic Psychological Stress and the Regulation of Pro-Inflammatory Cytokines: A Glucocorticoid-Resistance Model," Gregory E. Miller, Ph.D., Washington University at St. Louis; Sheldon Cohen, Ph.D., Carnegie Mellon University; A. Kim Ritchey, M.D., Children's Hospital of Pittsburgh; Health Psychology, Vol 21, No. 6.

Reporters: Gregory E. Miller, PhD can be reached by telephone at (314) 935-6595

The American Psychological Association (APA), in Washington, DC, is the largest scientific and professional organization representing psychology in the United States and is the world's largest association of psychologists. APA's membership includes more than 155,000 researchers, educators, clinicians, consultants and students. Through its divisions in 53 subfields of psychology and affiliations with 60 state, territorial and Canadian provincial associations, APA works to advance psychology as a science, as a profession and as a means of promoting human welfare.