We do not know much about how immune systems operate within the brain. We know much more about how certain moods and behaviors affect specific immune responses. Immunology is limited to the study of the immune response system and should not be confused with endocrine or hormonal response systems which are very different. For instance, the well known increases of cortisol and corticotropin-releasing hormone due to stress are hormonal responses.

The field of psychoneuroimmunology (PNI) is very new. The recognized father of PNI is Dr. Robert Ader, a psychiatrist at the University of Rochester Medical Center. His pioneering research in the late 1970s led to the discovery that immune responses could be behaviorally conditioned in rats. However, in an interview published in June 1999, Ader was concerned that there were too many "premature claims that the mind can cure cancer and other diseases." "There are data that show that psychosocial factors influence susceptibility to disease... but, there is no definitive evidence that psychosocial factors influence disease via changes in the immune system." His concerns have not changed since 1999.

The author of a recent, comprehensive New York Times article entitled "Is There a Link Between Stress and Cancer?" found almost no scientific evidence supporting the theory that stress may be a significant contributing factor to the occurrence or growth of any cancer. Other studies have shown a link between stress and decreased immune responses to different types of vaccinations. Although there were "dampened" responses, there is no proof that those decreased immune responses were significant enough to cause or contribute to illnesses.

The biggest problem with studying stress is the subjective quality of stress. Although it is possible to define stressors and to rate them as to their possible impact, what is stress to one person may not be stress to another. We do not yet know exactly what controls our experience of stress, whether it is mostly our mindset and programmed responses to fear-inducing situations, or if it is more biologically inherited. Some people may be intrinsically more "over-responsive" to fear than others.

There are only a few findings that are clear and useful for each of us. Laughter increases natural killer cells (NK cells are white blood cells that attack cancer cells) and gamma interferon levels. Relaxation techniques increase helper T-cells. These positive increases are known to persist for a least 12 hours. Although positive immune system responses are good, we still do not know for sure if they have significant protective effects against illnesses.

We might be tempted to conclude that since laughter and relaxation are good for the immune system that stress is not. However, it is just not that simple. My advice? Do whatever you can to learn and practice relaxation techniques and laughter to help keep your immune system "pumped up." While you are doing that, your experience of stress will automatically change for the better.

I hope that is helpful. For more information about mental wellness, please visit www.MentalWellness.ws. -- Best wishes, Dr. Ron.

Author Bio:

Ron Sterling, M.D. is a 61 year-old General and Geriatric Psychiatrist with a private practice in Seattle. He invites you to e-mail him at with any questions about mental wellness or emotional, relationship, or aging concerns. He is the only person who reads e-mail sent to Dr. Ron. Please be assured that your questions and identities are completely confidential and protected. For more information about Dr. Ron and for resources related to senior mental health, please go to SeniorMentalHealth.org. The content offered through Mind Matters is for information only and is not intended for medical, psychiatric, or psychological diagnosis or treatment. Never disregard professional advice or delay seeking it because of something you have read in this column. Read our Disclaimer. If you wish to understand more about Dr. Sterling's potential biases in health care advocacy, please check his Conflicts of Interest Disclosure Statement

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