A new understanding of why some people get sick when exposed to germs while others remain healthy is radically revising the popular concept of what causes illness. How resistant we are to. the microbes in our lives is a function of how well we are coping, which in turn depends largely on how we look at problems our "cognitive appraisal" and the chemical changes that our thoughts produce in our brains and bodies.

Growing knowledge about the influence of people's attitudes and appraisals on their physiological functions is forging a heady revolution in health sciences. Recent research has demonstrated, for instance, how our immunity is affected by what goes on in our heads, by hormonal changes that are brought on from poor coping or by direct effects of our central nervous systems.

Our cognitions (thoughts, beliefs, attitudes) and the social support we perceive in our lives can alter the levels of our hormones and neurotransmitters, the chemical messengers that carry on communication between our cells and largely govern the activity of many of our physical processes.

An expanded explanation of disease is emerging that is "bio psycho social," meaning that a person's mind, body and environment together determine whether he gets sick. Disease is not so much the effect of noxious, external forces the "bugs," both literal and figurative, in our lives as it is the faulty efforts of our minds and bodies to deal with them. Most of the "bugs," the literal kind, already reside in our bodies. When our responses to problems in life are excessive or deficient, the central nervous system and hormones act on our immune defenses in such a way that the microbes aid and abet disease. The balance is upset between us and our resident pathogens.

The term "pathogen" or germ, then, does not mean something that invariably "causes" illness or disease. Pathogens refer to bacteria, viruses or other microorganisms that have the potential to induce disease. Physician Andrew Weil, research associate in ethnopharmacology at Harvard and author of Health and Healing, reminds us:

“...this point must be stressed: external, material objects are never causes of disease, merely agents waiting to cause specific symptoms in susceptible hosts. Rather than warring on disease agents with the hope (vain, I suspect) of eliminating them, we ought to worry more about strengthening resistance to them and learning to live in balance with them more of the time.”

If we have poor coping skills, deficient social support and high stress, then the internal balance of our bodies may be easily upset and our resistance lowered. Weil adds: "At a time of impending breakdown of equilibrium, an agent of disease might find fertile ground in which to develop or might act as the straw that breaks the camel's back."

Illness or disease, then, occurs more from our vulnerability than from external agents that are "the cause" of our health problems. The more vulnerable we are, the more risk we run of getting sick. The factors that place us at risk range from our attitudes and appraisals in coping with stress to the kind of food we eat and the genes we inherit.

Our mind and behavior, our environment and our genetic predispositions are the common contributors to disease. The relative importance of each of these three spheres varies with the disease in question. A few diseases, like cystic fibrosis, are almost entirely genetic and require very little "push" from psychological or environmental influences to develop. On the other hand, the most prevalent diseases today are significantly affected by our coping styles (including our thinking) and our environment. Carcinogens in the environment or our diets may produce cancerous changes in our cells, but the evidence suggests that malignancy will not occur unless other risk factors are present and our immune systems are depressed.