In the past twenty years, twenty-eight states and the District of Columbia have passed some form of medical marijuana law. A new study, released today by Health Affairs as a Web First, studied nine clinical areas to find out if Medicaid enrollees in these states were less likely to fill prescriptions for these conditions, compared to enrollees in other states.

According to the study, in five of the nine clinical areas there was a significant negative association between the presence of state medical marijuana laws and prescriptions filled for each category by Medicaid beneficiaries. Furthermore, the authors estimate that if all states had had a medical marijuana law in 2014, the total savings for fee-for-service Medicaid could have been $1.01 billion. These results are similar to those in a study the authors conducted about the effects of medical marijuana laws on the number of prescriptions within the Medicare population, published by Health Affairs in July 2016.

For their evaluation, the authors used State Drug Utillization Data, collected by the Centers for Medicare and Medicaid Services (CMS). The data cover all drugs reimbursed by each state’s Medicaid program. “Our findings suggest that patients and physicians in the community are reacting to the availability of medical marijuana as if it were medicine,” the authors concluded.

“Our work adds to the literature that shows the potential clinical benefits of marijuana.  Since our findings also raise important questions about individual behavior and plausible safety concerns for patients who might forgo regular physician monitoring if switching from a prescription drug to marijuana, an important next step for medical marijuana law researchers will be to secure data on individual patients over time to assess these and related questions.”

Both authors are affiliated with the Department of Public Administration and Policy at the University of Georgia, in Athens.

This study will also appear in the May issue of Health Affairs.