Some observers maintain that PTSD is merely the latest label for an age-old condition. Symptoms associated with PTSD can be found in soldiers from antiquity to modern times, including the American Civil War. Opponents counter that PTSD is a diagnosis intentionally tailored to contemporary knowledge about anxiety disorders. Devising a retrospective diagnosis based on coincident symptoms ignores fundamental changes in interpretation of mental illness. Applying one era’s causation to another’s effects is anachronistic and illogical. Some veterans of the Union army experienced symptoms suggestive of PTSD, but their root causes were understood differently. Most attributions kept within the contemporary doctrine of physical causes of mental illness, but there were exceptions. Survivors of the Andersonville prison camp were more than twice as likely as non-prisoners to be diagnosed with a mental illness. Union veterans and physicians acted on the conviction that extraordinary torments were enough to produce psychological disabilities. Suicides are another indicator of Union veterans’ distinctive burden. The overall suicide rate for Massachusetts veterans from 1870 to 1900 considerably exceeded the rate among veterans in registration states in 2014.