Bachhuber cautioned that the exact mechanism underlying these study results is unclear, and that the findings don't prove a direct cause-and-effect relationship between medical marijuana laws and overdose deaths.
Flansbaum agreed. Although he called the paper "provocative" and "stimulating," he said it doesn't prove that medical marijuana reduces drug overdoses.
"There are so many things going on in states, whether it be cultural or through laws, it's hard to say what's the effect of the medical marijuana law versus everything else that's happening," Flansbaum said. "You don't know what causes what. The data is not that clean."
But these findings support previous studies that showed people who receive a prescription for medical marijuana tend to reduce the amount of other pain medications they use, said John Thomas, a health law expert and professor at the Quinnipiac University School of Law in Hamden, Conn.
There are some concerns that those patients might start abusing their medical marijuana, as they would a prescription painkiller, Thomas added.
"The good news about that is that marijuana doesn't tend to kill you, and it isn't as physically addictive as other medication," he said.
For more on prescription drug overdose, visit the U.S. Centers for Disease Control and Prevention.
SOURCES: Marcus Bachhuber, M.D., researcher, Center for Health Equity Research and Promotion, Philadelphia Veterans Affairs Medical Center; John Thomas, J.D., M.P.H., professor, Quinnipiac University School of Law, Hamden, Conn.; Bradley Flansbaum, D.O., M.P.H., hospitalist, Lenox Hill Hospital, New York City; Aug. 25, 2014, JAMA Internal Medicine
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