Post-traumatic stress disorder rarely turns people into killers, but soldiers with PTSD have been known to strangle their wives in bed while having flashbacks or nightmares, believing they're on the battlefield.
(n) a transition (in literary or theatrical works or films) to an earlier event or scene that interrupts the normal chronological development of the story, Ant. flash-forward
n. 1. a transition (in literary or theatrical works or films) to an earlier event or scene; also, the scene thus introduced. [ WordNet 1.5 ]
2. An unusually vivid recollection of a prior experience, often one that is traumatic, such as scenes from combat or a criminal assault, or induced by hallucinogenic drugs such as LSD; when accompanied by hallucinations it is called flashback hallucinosis. [ PJC ]