Medical marijuana
Medical marijuana in large prescription bottle.

A new study by researchers at the University of Georgia has revealed that American states that have approved medical cannabis laws saw a dramatic reduction in opioid use.

In a paper published yesterday, April 2 in the Journal of the American Medical Association, Internal Medicine, researchers examined the number of all opioid prescriptions filled between 2010 and 2015 under Medicare Part D, the prescription drug benefit plan available to Medicare enrollees.

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Researchers observed that in states with medical cannabis dispensaries, there is a 14.4 per cent reduction in use of prescription opioids and nearly a 7 percent reduction in opiate prescriptions in states with home-cultivation-only medical cannabis laws.

“Some of the states we analyzed had medical cannabis laws throughout the five-year study period, some never had medical cannabis, and some enacted medical cannabis laws during those five years,” said W. David Bradford, study co-author.

“So, what we were able to do is ask what happens to physician behavior in terms of their opiate prescribing if and when medical cannabis becomes available.”

Since California approved the first medical cannabis law in 1996, 29 states and the District of Colombia have approved some form of medical cannabis law.


“There is a growing body of literature that suggests cannabis may be used to manage pain in some patients, and this could be a major component of the reductions we see in the use of opiates,” Bradford said.

The researchers did not, however, see any significant reductions in the number of non-opioid drugs prescribed during the study period.

“In other studies, we examined prescription rates for non-opioid drugs such as blood thinners, flu medications and phosphorus stimulants, and we saw no change,” said Ashley Bradford, lead author of the study.

“Medical cannabis wouldn’t be an effective treatment for flu or for anemia, so we feel pretty confident that the changes we see in opioids are because there is a legitimate medical use.”

The researches, however, agreed that if medical cannabis is to become an effective treatment, there is still much work to be done; scientists will need to better understand the effects of the compounds in Cannabis and also arrive at a well-defined effective dose for patients.

“Regardless, our findings suggest quite clearly that medical cannabis could be one useful tool in the policy arsenal that can be used to diminish the harm of prescription opioids, and that’s worthy of serious consideration,” David Bradford added.