Most physical illnesses have psycho-somatic components and/or psychiatric complications.  Patients with psychiatric illnesses, as a whole, have more physical illness and more primary care visits than the general population.
Mind-body medicine focuses on the interactions among the brain, mind, body, and behavior, and on the powerful ways in which emotional, mental, social, spiritual, and behavioral factors can directly affect health.  It regards as fundamental an approach that respects and enhances each person's capacity for self-knowledge and self-care, and it emphasizes techniques that are grounded in this approach. 
Mind-body medicine typically focuses on intervention strategies that are thought to promote health, such as relaxation, hypnosis, visual imagery, meditation, yoga, biofeedback, tai chi, qi gong, cognitive-behavioral therapies, group support, autogenic training, and spirituality. The field views illness as an opportunity for personal growth and transformation, and health care providers as catalysts and guides in this process. 
The concept that the mind is important in the treatment of illness is integral to the healing approaches of traditional Chinese and Ayurvedic medicine, dating back more than 2,000 years.  This concept was also noted by Hippocrates, who recognized the moral and spiritual aspects of healing, and believed that treatment could occur only with consideration of attitude, environmental influences, and natural remedies (ca. 400 B.C.).  While this integrated approach was maintained in traditional healing systems in the East, developments in the Western world by the 16th and 17th centuries led to a separation of human spiritual or emotional dimensions from the physical body. This separation began with the redirection of science, during the Renaissance and Enlightenment Eras, to the purpose of enhancing humankind's control over nature. Technological advances demonstrated a cellular world that seemed far apart from the world of belief and emotion.  Fixing or curing an illness became a matter of science (i.e., technology) and took precedence over, not a place beside, healing of the soul. 
In the 1920s, Walter Cannon's work revealed the direct relationship between stress and neuroendocrine responses in animals. Coining the phrase "fight or flight," Cannon described the primitive reflexes of sympathetic and adrenal activation in response to perceived danger and other environmental pressures (e.g., cold, heat).  Hans Selye further defined the deleterious effects of stress and distress on health.  At the same time, technological advances in medicine that could identify specific pathological changes, and new discoveries in pharmaceuticals, were occurring at a very rapid pace.  The disease-based model, the search for a specific pathology, and the identification of external cures were paramount, even in psychiatry.
During World War II, the importance of belief reentered the web of health care. On the beaches of Anzio, morphine for the wounded soldiers was in short supply, and Henry Beecher, M.D., discovered that much of the pain could be controlled by saline injections. He coined the term "placebo effect," and his subsequent research showed that up to 35 percent of a therapeutic response to any medical treatment could be the result of belief.  Investigation into the placebo effect and debate about it are ongoing.
Since the 1960s, mind-body interactions have become an extensively researched field. The evidence for benefits for certain indications from biofeedback, cognitive-behavioral interventions, and hypnosis is quite good, while there is emerging evidence regarding their physiological effects.  The following is a summary of relevant studies.
Information on this page was obtained from the following website:
National Center for Complementary and Alternative Medicine: http://nccam.nih.gov/health/backgrounds/mindbody.pdf