Post-traumatic stress disorder (PTSD) - Symptoms and causes - Mayo Clinic
Some of the better novels/histories about war cover post traumatic stress disorder in just about every war they are describing especially if horrible things happened in those conflicts. Anything from the Battle of Agincourt to the Battle of Okinawa to those fighting in Afghanistan now.
I have also seen it from first responders as I watched my uncle's face as he described cleaning up of an airplane crash near O'Hare Airport in the late 1970s. He was the Fire Chief of Itasca, Illinois. But he did not like talking about it all that much.
American Airlines Flight 191 - Wikipedia