To interpret the prescribing behavior of clinicians, researchers used “fuzzy-trace theory,” an innovative approach to evaluating decision-making under risk, developed by study co-author Dr. Valerie Reyna. According to fuzzy-trace theory, providers prefer to rely on simple “gists” to make medical decisions, even though they are able to make decisions involving complex tradeoffs between benefits and harms. When deciding whether or not to prescribe an antibiotic for a particular patient, two gists dominated: (1) “why not take a risk,” in which providers perceived the risks from antibiotics as negligible compared to the patient’s current illness, and (2) “antibiotics may be harmful,” in which the provider agreed that the side effects of antibiotic therapy could be significant.
The clinicians who treated patients in this study followed a well-documented history of overprescribing in the United States: overall, antibiotics were prescribed for three-quarters of patients with diagnoses sometimes requiring them, according to guidelines; and antibiotics were prescribed for half the patients with diagnoses for which antibiotics are definitely not indicated.
But clinicians were true to their gists: those in the “why not take a risk” group were about fifty percent more likely to prescribe antibiotics than those in the “antibiotics may be harmful” group. This was especially true when patients were diagnosed with conditions that, according to prescribing guidelines, do not actually require antibiotics. Patients with pneumonia—where antibiotics are almost always indicated—were prescribed the drugs in almost all cases, regardless of gist.