by Paul Armentano, NORML Deputy DirectorApril 2, 2018

The enactment of marijuana legalization laws is associated with a significant reduction in the number of opioids prescribed and filled, according to a pair of studies published online today in the journal JAMA Internal Medicine.

In the first study, investigators from the University of Kentucky and Emory University assessed the association between medical and adult-use marijuana laws with opioid prescribing rates and spending among Medicaid enrollees. They reported:

“State implementation of medical marijuana laws was associated with a 5.88 percent lower rate of opioid prescribing. Moreover, the implementation of adult-use marijuana laws, which all occurred in states with existing medical marijuana laws, was associated with a 6.38 percent lower rate of opioid prescribing. … [T]he further reductions in opioid prescribing associated with the newly implemented adult-use marijuana laws suggest that there were individuals beyond the reach of medical marijuana laws who may also benefit from using marijuana in lieu of opioids. Our finding that the lower opioid prescribing rates associated with adult-use marijuana laws were pronounced in Schedule II opioids further suggest that reaching these individuals may have greater potential to reduce the adverse consequences, such as opioid use disorder and overdose.”

The full text of the study, “Association of Medical and Adult-Use Marijuana Laws With Opioid Prescribing for Medicaid Enrollees,” is available here.

In the second study, University of Georgia researchers evaluated the association between the enactment of medical cannabis access laws and opioid prescribing patterns under Medicare Part D. They reported:

“This longitudinal analysis of Medicare Part D found that prescriptions filled for all opioids decreased by 2.11 million daily doses per year from an average of 23.08 million daily doses per year when a state instituted any medical cannabis law. Prescriptions for all opioids decreased by 3.742 million daily doses per year when medical cannabis dispensaries opened. … Combined with previously published studies suggesting cannabis laws are associated with lower opioid mortality, these findings further strengthen arguments in favor of considering medical applications of cannabis as one tool in the policy arsenal that can be used to diminish the harm of prescription opioids.”

The full text of the study, “Association Between US State Medical Cannabis Laws and Opioid Prescribing in the Medicare Part D Population,” is available here.

Both findings are consistent with those of numerous prior studies finding that cannabis access is associated with reduced rates of opioid use and abuse, opioid-related hospitalizations, mortality, and overall prescription drug spending. A compilation of these studies is available in the NORML fact-sheet here.