Need to see a doctor about a health issue? Choose carefully, because a new Yale study shows that physicians’ treatment recommendations could vary drastically depending on their political affiliations.

The study, published in the Proceedings of the National Academy of Sciences, was a collaboration between Yale political science professor Eitan Hersh and Yale psychiatrist Matthew Goldenberg ’99 MED ’03. Marrying an analysis of voter registration databases with physician surveys, the Yale researchers found that a doctor’s political leanings could be linked to both how seriously they rate politically charged health issues and their recommendations for treatment plans. According to the co-authors, the study is the first to examine physician behavior in the context of political bias.

“There have been many studies in the past that have looked at racial and gender biases toward patients, but this is the first study that looks at partisanship bias in health care,” said Hersh.

To assess differences in physician behavior, Hersh and Goldenberg asked doctors nationwide to rate how seriously they considered various health-related problems. The study found that Republican doctors were generally more concerned with issues of abortion and marijuana, whereas Democrats emphasized the gravity of firearm storage. The researchers found, however, that this discrepancy vanished in relation to non-political issues such as cigarette smoking, depression and sex work.

The study also showed that these cognitive biases manifested as treatment differences. Republicans were more likely to discuss the legal risks of marijuana, refer patients to abortion counselors and ask patients about safe gun storage rather than urging them not to store firearms at all.

According to Hersh, the unveiling of these partisan influences should extend beyond simple awareness.

“If you’re a liberal doctor and you’re not comfortable talking about issues like gun control, you need to inform yourself about that issue,” Hersh said. “Working in a hospital that is frequented by gunshot victims, you need to understand ‘what does it mean to store a gun safely.’”

Goldenberg expressed a similar sentiment but added that he was cautious of over-interpreting the results of their study, which he described as “only one study” and the first of its kind. He argued that more studies need to be done before deciding what actions to take in order to mitigate such political bias.

Hersh said that he and Goldenberg already have plans to follow up the results of their study. He added that since their research focused only on primary care physicians, they intend to repeat the study for other medical specialties such as gynecologists. They also plan to assess clinical outcomes instead of physician surveys by tapping into public Medicare and Medicaid databases to study behaviors such as reimbursement trends.

Goldenberg noted that medical education plays an important role in reducing physician bias, arguing that pre-med students and medical students alike should have an awareness of the “social contract” of health.

At Yale, medical students currently have the option of taking a student-run course called US Health Justice, which encourages students to confront and discuss common biases in arenas such as race and socioeconomic status. Ram Sundaresh MED ’19 said he hopes that the administration will integrate the course into the broader medical curriculum.

“Our curriculum mostly just teaches us that bias exists and that we all have implicit biases of one kind or another,” Sundaresh said. “But for the sake of our patients we must do more.”

And indeed it is patients who are the impetus for this discussion. Despite their study’s focus on physician behavior, Hersh and Goldenberg said patient empowerment is the true goal of their research.

“If you’re a gay patient, you should be able to choose a doctor whom you feel comfortable talking to” said Hersh. “Having more information is very useful for patients, especially since we now know doctors are not neutral arbiters.”

Funding for the study was provided by the Yale Department of Psychiatry and the Institution for Social and Policy Studies.