Psychoneuroimmunology

Solid research is now confirming what many physicians have long observed: That the state of the mind directly affects physical illness.
The scientific investigation of how the brain affects the body's immune cells and how the immune system can be affected by behavior is called psychoneuroimmunology, a term coined in 1964 by Dr. Robert Ader.
Under the support of a National Institutes of Mental Health grant, physicians and researchers David Spiegel and Sara Stein write, "Once believed to be autonomously functioning mechanisms, the nervous, endocrine, and immune systems are now known to be integrally connected, with exquisitely sensitive communications and interactions.
These and other researchers have shown that what we think and how we feel appear to have powerful effects on the biological functions of our bodies, especially on the immune system. It also shows that there is a complex, dynamic interaction between the mind and the body. Finally, it opens the revolutionary possibility tha twe can work with our physicians by virtue of our attiudes and our emotions, not just our biological systems.
-Information found from Mind/Body Health THe Effects of Attitudes, Emotions, and Relationships by Keith J. Karren