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Fast findings

Study reveals link between medical marijuana, opioid overdoses

October 21, 2014

States that allow medical marijuana tend to have lower rates of overdose from opioid painkillers.

That's the conclusion of researchers with VA and the University of Pennsylvania.

Their study tracked data from all 50 states, including the 13 that had passed medical marijuana laws by 2010. Today, 23 states in all, plus the District of Columbia, have such laws on the books.

Based on data from 1999 through 2010, the states with medical cannabis laws had about a 25 percent lower rate of deaths from opioid overdoses, on average, compared with states without the laws. The overdose rates tended to drop lower with each year following the enactment of the laws.

Lead author Dr. Marcus Bachhuber, a Robert Wood Johnson Foundation Clinical Scholar at the Philadelphia VA Medical Center, told news@JAMA that the study was prompted by his discussions with many patients who had found marijuana effective for their chronic pain. He and his coauthors thought they might see a trend wherein patients were increasingly replacing or supplementing opioid drugs with marijuana, thereby lessening overall opioid use—and, in turn, overdose rates.

"Alternatively," he noted, "there is still debate about whether medical marijuana might lead patients to use other drugs, so opioid overdose might have increased. We thought there could be a change in either direction, and that's why we decided to study it."

Bachhuber, also with VA's Center for Health Equity Research and Promotion, said further study is needed to better understand how medical marijuana laws interact with policies aimed at cutting opioid overdose. (JAMA Internal Medicine, online Aug. 25, 2014)