In 1996, the Office of the Inspector General Evaluation Report on the Management of Combat Stress Control in the Department of Defense noted that “Combat stress is not new”, its documentation “dat[ing] back to the Civil War.” Using data from that conflict, World War I, World War II, Korea, and Vietnam, psychiatrist and war historian Dr. Stephen A. Goldman will examine how evolving concepts and knowledge of combat-related stress led to the American Psychiatric Association’s milestone 1980 classification of posttraumatic stress disorder (PTSD). He will then discuss the ongoing revision of PTSD diagnostic criteria based on accumulating experience and research from subsequent wars, and the actual (as opposed to popularly believed) extent of PTSD among veterans, up to and including those who have served in Iraqi, Afghanistan, or both theaters.