When researchers built seven fictional patients who all clearly qualified for a sleep study and ran them past the five most widely used free chatbots, the tools gave correct advice every single time. Then the team ran the same medical facts again with one change. The patient played down symptoms and resisted the idea of seeing a specialist. Correct advice survived in only 64 percent of those conversations.
The finding, presented at the European Respiratory Society Congress in Barcelona, tested ChatGPT, Google Gemini, Claude, DeepSeek and Grok across 700 total conversations. Half of those, 350, involved a cooperative patient. All 350 ended with correct advice to seek specialist assessment. The other 350 involved a reluctant patient with identical clinical details, and 225 ended correctly. The gap was produced by tone alone.
