When the doctor says, “I could prescribe antibiotics for your sniffles, but it’s probably a virus – not bacterial,” do you decline? Many patients expect antibiotics, although overprescription is a major factor driving one of the biggest public health concerns today: antibiotic resistance.

Now researchers at Cornell, George Washington and Johns Hopkins universities have figured out why: “Patients choose antibiotics because there’s a chance [prescription medications] will make them better, and they perceive the risks of taking antibiotics as negligible,” says Cornell psychologist Valerie Reyna.

With her co-authors, the professor of human development has published new research with important implications for communicating about antibiotics: “Germs Are Germs, and Why Not Take a Risk? Patients’ Expectations for Prescribing Antibiotics in an Inner-City Emergency Department,” in the journal Medical Decision Making.

That’s encouraging news for health educators, Reyna says, noting: “Patients might expect doctors to prescribe antibiotics because patients confuse viruses and bacteria – and think antibiotics will be effective for either. Most educational campaigns attempt to educate patients about this misconception. However, we found fewer than half of patients in an urban ER agreeing with the message, ‘germs are germs.’”

Patients who understand the difference between viruses and bacteria – and take antibiotics anyway – are making a strategic risk assessment, Reyna says: “Our research suggests that antibiotic use boils down essentially to a choice between a negative status quo – sick for sure – versus taking antibiotics and maybe getting better. This risk strategy promotes antibiotic use, particularly when taking antibiotics is perceived as basically harmless.”

Fuzzy-trace theory

The Broniatowski-Klein-Reyna study is the first to apply “fuzzy-trace” theory to how people think about antibiotics. The theory predicts that patients make decisions based on the gist (or simple bottom line) of information.

As Reyna explains: “The goal is to make better decisions, getting antibiotics to patients who need them but not overusing them so the rest of the public is safe. Understanding how patients think is crucial because their expectations influence doctors’ decisions.”

Adds David Broniatowski, assistant professor of engineering management and systems engineering at GWU, and the report’s first author: “We need to fight fire with fire. If patients think that antibiotics can’t hurt, we can’t just focus on telling them that they probably have a virus. We need to let them know that antibiotics can have some pretty bad side effects, and that they will definitely not help cure a viral infection.”

The third author is Dr. Eili Klein, assistant professor in the Department of Emergency Medicine at the Johns Hopkins University and a fellow at the Center for Disease Dynamics, Economics and Policy.

Reyna is the director of the Human Neuroscience Institute, co-director of the Cornell University Magnetic Resonance Imaging Facility, and a co-director of the Center for Behavioral Economics and Decision Research, all in the College of Human Ecology. She is a developer of “fuzzy-trace theory,” a model of the relation between mental representations and decision making that has been widely applied in law, medicine and public health.

The study was supported, in part, by funds from the National Institutes of Health and the U.S. Department of Homeland Security.