The original diagnosis was probably shell shocked. Like if you were on the receiving end of a canon shell. In researching the pension record for my great great grandfather, Joseph Rowell I discovered he made a claim of shell shock during his civil war service.
He was serving in the 11th Florida Infantry in February 1865 near Petersburg, Virginia when a Union artillery shell exploded next to him. He was thrown to the ground on top of several canteens and received a "rupture."