When an organ as complex as our brain malfunctions, some very puzzling mental delusions can result. One of the most extreme delusions ever observed was recorded by a French psychiatrist during l’entre-deux-guerres. The case involved a 53-year-old Parisian seamstress who “had become convinced those around her were being kidnapped by strange creatures known as ‘sosies’, which imprisoned her loved ones underground as they plotted to steal all her property.” The woman claimed that every day her daughter went off to school, she was replaced by an identical impostor.
What’s the Big Idea?
While such extreme cases were once undoubtedly treated in somewhat mystical fashion, today we know that massive delusions are often caused by brain trauma, stroke or neurological illness. In many cases, delusions turn on problems of identification. “Once these mistaken identifications start occurring, the brain then needs to take the next big step by actually deciding these errors are actually indicative of a larger reality.” Research suggests that people prone to ignoring evidence that contrasts their viewpoint are more likely to make such delusional leaps.