Stress and Disease : Part 2

by National Institute of Health

(Page 2 of 2)

Controlling the Immune Response

Problems between the brain and the immune system can go the other way, too. If for some reason you're unable to make enough of these brain stress hormones, you won't be able to turn off the immune cells once they're no longer needed.

"There has to be an exit strategy for these battles that are being fought by the immune system, and the brain provides the exit strategy through stress hormones," Dr. Sternberg says. "If your brain can't make enough of these hormones to turn the immune system off when it doesn't have to be active anymore, then it could go on unchecked and result in autoimmune diseases like rheumatoid arthritis, lupus, or other autoimmune diseases that people recognize as inflammation."

Dr. Sternberg says that there are several factors involved in these autoimmune conditions. There are many different effects that the brain and its nervous system can have on the immune system, depending on the kinds of nerve chemicals that are being made, where they're being made, what kind of nerves they come from, and whether they're in the bloodstream or not. Still, at least part of the problem in these diseases seems to involve the brain's hormonal stress response.

"So if you have too much stress hormone shutting down the immune response, you can't fight off infection and you're more susceptible to infection," Dr. Sternberg concludes. "Too little stress hormones and the immune response goes on unchecked and you could get an inflammatory disease." Pinpointing the Problems

Why these miscommunications between the brain and the immune system come about is still largely unknown, and involves many genes and environmental factors. But by studying animals, scientists have finally been able to start understanding how the miscommunications occur.

Dr. Sternberg first started publishing work on the links between the brain and the immune system back in 1989 studying rats with immune problems. "In many of these cases it's very hard to show the mechanism in humans," Dr. Sternberg explains, "but you can show the mechanism in animals because you can manipulate all the different parts of the system and you can begin to understand which parts affect which other parts." It has taken "a good ten years" to gather enough evidence in human studies to show that the principles her lab uncovered in rats were also relevant to human beings.

Drugs that have been tested in rats to correct brain/immune system problems have had unpredictable effects. That is because nothing happens in isolation when it comes to the brain and the immune system. Dr. Sternberg points out that our bodies are amazing machines which at every moment of the day are constantly responding to a myriad of different kinds of stimuli - chemical, psychological, and physical. "These molecules act in many different ways in different parts of the system," she says. Understanding how the brain and the immune system work together in these different diseases should help scientists develop new kinds of drugs to treat them that would never have occurred to them before.

Taking Control Now

Dr. Sternberg thinks that one of the most hopeful aspects of this science is that it tells us it's not all in our genes. A growing number of studies show that, to some degree, you can use your mind to help treat your body. Support groups, stress relief, and meditation may, by altering stress hormone levels, all help the immune system. For example, women in support groups for their breast cancer have longer life spans than women without such psychological support.

There are several components of stress to think about, including its duration, how strong it is, and how long it lasts. Every stress has some effect on the body, and you have to take into account the total additive effect on the body of all stressors when considering how to reduce stress.

Perhaps the most productive way to think about stress is in terms of control. Dr. Sternberg shows a slide of an F-14 jet flying sideways by the deck of an aircraft carrier, its wings completely vertical. "The Navy Commander who flew that jet told me that he was the only one in the photo who was not stressed, and that's because he was the one in control. The officer sitting in the seat ten feet behind him was in the exact same physical situation but was not in control. Control is a very important part of whether or not we feel stressed.

So if you can learn to feel that you're in control or actually take control of certain aspects of the situation that you're in, you can reduce your stress response." Studies show that gaining a sense of control can help patients cope with their illness, if not help the illness itself.

Until science has more solid answers, it can't hurt to participate in support groups and seek ways to relieve stress, Dr. Sternberg says. But what you need to remember is if you do these things and you're not successful in correcting whatever the underlying problem is, it's not your fault because there's a biology to the system. "You need to know the benefits of the system," she says, "but its limitations as well." In other words, try not to get too stressed about being stressed.

About the Author

NIH is the nation's medical research agency - making important medical discoveries that improve health and save lives. The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research.