Two new studies published in the Journal of the American Medical Association are adding weight to the argument that cannabis legalization can significantly reduce opioid consumption. The research found that when states legalize marijuana, either medicinal or recreational, a drop in opioid prescriptions can result.

Both studies looked at the number of opioid prescriptions filled over a five-year period across several US states that passed medical and/or recreational marijuana laws. The results identified a significant drop in opioid prescriptions whenever medical marijuana laws went into effect. Opioid prescription rates dropped even further in states that moved from medical marijuana laws into broader recreational 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," says W. David Bradford, co-author on one of the studies. "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."

While these are still only observational correlations, the researchers are confident the drops in opioid prescriptions can be related to the introduction of legal marijuana. No observations of reductions in rates of non-opioid prescriptions were identified during the study.

"We examined prescription rates for non-opioid drugs such as blood thinners, flu medications and phosphorus stimulants, and we saw no change," says Ashley Bradford, lead author of the study with David Bradford. "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 of cannabis because there is a legitimate medical use."

Prior research has effectively found that marijuana is an effective pain relief medication. A 2017 study examining the efficacy of marijuana as a direct replacement for opioid pain medication surveyed nearly 3000 medical marijuana patients. A stunning 97 percent of subjects either agreed or strongly agreed that marijuana helps them decrease the amount of opiates they consume, and 81 percent agreed or strongly agreed that marijuana alone was more effective than marijuana in combination with an opioid.

Not everyone is convinced by the idea that legalized marijuana can positively affect opioid consumption rates. A long-standing argument suggests that marijuana in fact results in a person being more likely to develop an opioid use disorder. While this may seem like a new spin on the classic "gateway drug" idea, a recent study did in fact conclude that marijuana use does correlate with an increase in the risk of non-medical prescription opioid use.

These studies do seem to be outweighed by research suggesting the contrary though. A great deal of study over the past few years continues to find that when medical marijuana laws are passed in a state, opiate usage drops. Of course, it is important to note that all of these studies are simply revealing a correlation, and not causation, but considering there is evidence showing cannabinoid and opioid receptor systems trigger similar brain signaling pathways, this is not an unreasonable association to observe.

At the very least, it seems like medical marijuana can play a part in helping tackle the dramatic opioid crisis that is currently sweeping the United States.

"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," says Bradford.

The two new research papers were published in JAMA (1) (2).