Well, the term was coined in the late 1970s, so it obviously wasn't called that.
But some psychiatrists familiar with the disorder claim to find references to its symptoms in Shakespeare - "Henry IV" in particular.
One of the problems with trying to find these kinds of parallels in history is that Psychiatry didn't exist yet, so no one would have pieced it all together yet. And wouldn't for several centuries.
But remember, there's a reason that Phobos and Deimos accompanied their father Ares into battle in Greek mythology. Even then, there was a specific kind of fear and terror associated with war, different from any other type.