Emotions and Behavior
When an individual remains under prolonged emotional tension, physiological changes may accumulate. This condition may produce disturbances in behavior, mostly because the prolonged activation of the autonomic nervous system brings about deviations from normal physiological functioning. In 1938 the American psychiatrist Flanders Dunbar presented a strong case for the role of emotion in producing physical illness, reporting evidence that the response of the physiology of the body to prolonged emotional tension may produce psychosomatic symptoms. Such symptoms are not initiated by microbes or by other traditional causes of physical diseases but are seen as the consequences of emotional tensions. Hence, they are called psychosomatic illnesses, or illnesses of psychogenic origin.
This concept of the causal role of emotions in producing physical symptoms began to receive prominence late in the 19th century when the French neuropsychiatrist Jean Charcot reported his studies of the emotional factors in hysteria.
Sigmund Freud also described the emotional basis of physical symptoms in hysteria and in other forms of neurosis. In the United States, Adolf Meyer, the Johns Hopkins neuropsychiatrist, developed during the first three decades of the 20th century what he called the theory of psychobiological parallelism. He stressed the role of emotional factors in both physical and mental health. Cannon reported his famous experiments on the physiological effects of acute emotion in 1938. During World War II, military psychiatrists reported numerous instances of profound changes in bodily function as well as in mental stability that appear to have been precipitated by intense and prolonged emotional states.