Jonathan R. Davidson, M.D., is a professor of psychiatry and the director of the Anxiety and Traumatic Stress Program at Duke University Medical Center. He has received awards from the American Psychiatric Association, the American psychopathological Association, and the American Medical Association for his contributions to psychiatry, as well as a National Institutes of Health grant for a groundbreaking study of herbs. Henry Dreher is a veteran science writer who has coauthored numerous articles and books.