Exposure to media information about a disease can cause doctors to misdiagnose similar-looking clinical cases.

PURPOSE: Anecdotal evidence indicates that exposure to media-distributed disease information, such as news about an outbreak, can lead physicians to errors; influenced by an availability bias, they misdiagnose patients with similar-looking but different diseases. The authors investigated whether exposure to media-provided disease information causes diagnostic errors and whether reflection (systematic review of findings) counteracts bias. METHOD: In 2010, 38 internal medicine residents first read the Wikipedia entry about one or another of two diseases (Phase 1). Six hours later, in a seemingly unrelated study, they diagnosed eight clinical cases (Phase 2). Two cases superficially resembled the disease in the Wikipedia entry they had read (bias expected), two cases resembled the other disease they had not read about (bias not expected), and four were filler cases. In Phase 3, they diagnosed the bias-expected cases again, using reflective reasoning. RESULTS: Mean diagnostic accuracy scores (Phase 2; range: 0-1) were significantly lower on bias-expected cases than on bias-not-expected cases (0.56 versus 0.70, P = .016) because participants misdiagnosed cases that looked similar to a Wikipedia description of a disease more often when they had read the Wikipedia description (mean = 0.61) than when they had not (mean = 0.29). Deliberate reflection (Phase 3) restored performance on bias-expected cases to pre-bias levels (mean = 0.71). CONCLUSIONS: Availability bias may arise simply from exposure to media-provided information about a disease, causing diagnostic errors. The bias's effect can be substantial. It is apparently associated with nonanalytical reasoning and can be counteracted by reflection.