Every war has had its own terms for the invisible scars left by combat, now known as post-traumatic stress disorder. Here is a brief history of PTSD on the battlefield:

Soldier's heart. The term was coined during the Civil War to describe the dizziness, shortness of breath, chest pain, and other symptoms that soldiers experienced in battle. It came back into use in the 1950s, when President Dwight Eisenhower's personal physician used it to describe the physiological effects of combat on the heart.

Shell shock. Surgeons during World War I used the phrase to describe soldiers who were dazed, confused, blind, deaf, or paralyzed for no apparent reason. Doctors believed the problem was caused when a bursting shell upset the workings of the brain, and that the only cure was to return home to recuperate-if you were an officer, that is. Regular soldiers with shell shock were often branded cowards.

Battle fatigue. World War II, which saw huge numbers of soldiers discharged for psychological problems stemming from fear and exhaustion, established the idea that external events like warfare could have psychological consequences. Until then, soldiers were believed to suffer breakdowns for mostly biological reasons, such as a weak nervous system. When the war began, the military believed that by picking the right soldiers, it could limit losses to battle fatigue. By war's end, it understood that every man has his breaking point.

Post-Vietnam syndrome. In the early 1970s, a group of psychiatrists used this term to describe a delayed reaction to combat that included alienation, depression, anger, and sleeplessness. Their work, and activism on the part of Vietnam vets, would become the impetus for diagnosing PTSD as a medical condition.

Post-traumatic stress disorder. In 1980, the American Psychiatric Association officially recognized PTSD. The designation gave victims a medical diagnosis to explain their sometimes debilitating responses to trauma and led to the development of several effective treatments for stress disorders.

Source: US News