There were 58 opioid prescriptions written for every 100 Americans in the United States in 2017, according to Mara Hollander. And she thinks she and her co-authors on a new Pitt study have found part of the reason why.

“That is a tremendous amount of prescribing in a country that is struggling with an opioid epidemic,” Hollander, a doctoral student in Pitt Public Health and the lead author of a new Pitt study on opioid prescriptions, said in a press release.

Hollander said she and her co-authors have found a consistent factor that led doctors to prescribe opioids — gifts from pharmaceutical companies. The companies are required by law to report the value of the gifts they give to physician-researchers, which can include consulting fees, travel and lodging, education and more.

The study, published Oct. 30 in the Journal of General Internal Medicine, found that physicians across a number of specialties are more likely to prescribe opioids to their patients if the physicians have received gifts from pharmaceutical companies.

The increase in likelihood varies across specialty, the researchers found. Primary care physicians, for instance, were 3.5 times more likely to prescribe opioids to patients if they had received gifts from pharmaceutical companies totaling more than $100. But psychiatrists and neurologists who received gifts on the same level were 13 times more likely to prescribe opioids.

Opioid giants Insys and Purdue were responsible for more than two-thirds of the gifts granted to the 236,000 physicians included in the study, though a total of 18 companies provided gifts related to opioids.

Senior author Marian Jarlenski, an assistant professor of health policy and management at Pitt Public Health, said in the release that although overdose death rates have leveled off in the last year, the opioid epidemic is “nowhere close to being over,” and politicians need to continue to seek solutions to the crisis with the new findings in mind.

“I would encourage policymakers and state and federal health officials to really dig into these findings and develop interventions that address this relationship between pharmaceutical company gift-giving and opioid prescribing,” Jarlenski said.