In some cases, a single altered detail, such as a friend's new hair style, may trigger jamais vu.
Modern victims tend to blame extraterrestrial aliens or secret government experiments.
In 1897, in Ireland, recounts Dr. George, Michael Cleary became convinced his wife Bridget was an imposter, and tortured her to death trying to extract a fairy confession. Cleary got 20 years for manslaughter. This is one reason NASA never schedules a planned walk any earlier than the third day in orbit. Exactly what it is is still a mystery, but most astronauts are over it in a few days. Rookies will usually spend their first day floating around with a plastic barf bag sticking out from a pocket.