Sam Cade said:It was dropped in the DSM-5.
That was my point. You may be aware of the history of amok (and related behavior) in isolated, non-industrialized cultures. "Amok" is a Malaysian word, and other cultures and languages have similar concepts.
It is comforting to think that those that kill en masse are bat-guano-insane, and terrifying to think they are more or less as sane as we are.