COVID-19 has been associated with increases in opioid overdose deaths, which may be in part because the pandemic limited access to buprenorphine, a treatment used for opioid dependency, according to a new study led by Princeton University researchers.

The researchers found that Americans who were already taking opioids did not experience disruptions in their supply. Patients who were not previously taking opioids for pain management were less likely to receive a new prescription in the first months of the pandemic, but prescriptions for new patients soon bounced back to previous levels.

At the same time, fewer new patients entered into medication-assisted treatment for opioid addiction, which may have contributed to a spike in overdose deaths, according to the study, which was published in the JAMA Network Open, a journal of the American Medical Association.