IT IS difficult to pick up a newspaper, magazine, or medical journal today without reading about the role of stress in causing hypertension, heart disease, ulcer, cancer, emotional illness, or an upset in a sporting event. A recent edition of the New York Times had front-page headlines proclaiming that the "Shah's Army Is Showing Stresses," and a Sunday edition told us that Bess Truman was released from the hospital suffering from hypertension and "abdominal stress," while on the next page, a psychiatrist warns that "holiday travel can lead to stress and hostility." Neurosurgeons at major leading institutions claim to be able to improve dramatically the recovery of 10,000 patients with severe head injuries each year by giving barbiturates to comatose patients "to stop the brain from working during the period when it is under most stress." We are told that "stress has surpassed the common cold as the most prevalent