Many Americans mistakenly conclude they have a rare illness after attempting self-diagnosis on the Internet, according to a recent study by researchers are Microsoft. The company conducted the study to improve its own search engine.

Microsoft studied health-related Web searches on popular search engines and surveyed 500 of its employees about their health-related searching. Microsoft’s Eric Horvitz, an artificial intelligence expert and medical school grad, says Web search engines can increase our health-related anxieties and lead us to believe worst-case scenarios.