 The addition of the term to the DSM-III was greatly influenced by the experiences and conditions of U.S. military veterans of the Vietnam War.Due to its association with the war in Vietnam, PTSD has become synonymous with many historical war-time diagnoses such as railway spine, stress syndrome, nostalgia, soldier's heart, shell shock, battle fatigue, combat stress reaction, or traumatic war neurosis.Some of these terms date back to the 19th century, which is indicative of the universal nature of the condition.