If you spent part of the past two years asking an AI chatbot why your eyelids looked darker and your eyes felt gritty, there is a chance you were told about a condition called bixonimania. It does not exist. It never did.
The disorder was invented in 2024 by Almira Osmanovic Thunström, a medical researcher at the University of Gothenburg in Sweden, as a deliberate stress test to see whether large language models could filter obvious nonsense from the medical information they provide to the public. Nature documented the results in a news feature published in April. The models did not filter it. Within weeks of two fabricated preprints appearing online, Microsoft's Copilot, Google's Gemini, Perplexity and ChatGPT were all describing the invented illness to users. One of them suggested seeing an eye specialist.
