Study: Legal marijuana appears to reduce prescription opioid abuse

States that have legalized marijuana appear to see a significant reduction in opioid prescriptions, according to a new study by Journal of the American Medical Association.

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Based in part on federal prescription data, the JAMA study shows that in states with either legal medical or recreational pot, Medicaid patients appear to be turning to cannabis for chronic pain management instead of more potent and addictive opioids such as oxycodone. The data led researches to conclude that, “marijuana liberalization may serve as a component of a comprehensive package to tackle the opioid epidemic.”

Dr. Andrew Saxon, a University of Washington psychiatry and behavioral sciences professor, said the data and the report are compelling but not conclusive.

“What we are seeing is a strong trend to suggest that states that have made good quality cannabis legally available to individuals there seems to be a reduction in opioid prescribing,” Saxon said. “But there is much we don’t know.”

The study, published earlier in the week, parallels other research that has linked cannabis-based pain management with a decline in legal opioid prescriptions. Based on Medicaid prescription data starting in 2011, data compares states with and without legal pot.  The numbers indicate that opioid prescriptions on average decline approximately six percent when legal pot becomes readily available. Legal opioid prescriptions have, in part, been blamed for the nation’s opioid epidemic.

Pot became legal in Washington state in 2013 after the passage of Initiative 502 the prior November. Nine states at the District of Columbia have legal, recreational pot and another seven states allow medical marijuana. The recent JAMA study is one of several  research efforts — including one partially sponsored by the Washington State Department of Health — that have linked legal pot to a decline in opioid prescriptions.

Saxon cautioned that the existing studies are almost exclusively what researchers call “associative” but not “causal.” In other words, two events — a drop in prescriptions in the same place where pot became legal– might be parallel but still not related. Part of the reason the data has not been solidly linked, he said, is the historic difficulty in domestic marijuana research.

Pot remains federally classified as a Schedule I drug which is defined by the Drug Enforcement Administration as having a “high potential for abuse and the potential to create severe psychological and/or physical dependence.” And as Schedule I — a classification more severe than cocaine and methamphetamine — it is also deemed by the DEA as having no medical value.  In research facilities that get federal funding, such as universities, that designation can put other funding at risk if any non-federally sanctioned pot-related research is done.

Moreover, if a researcher can successfully fight through the reams of paperwork to secure federally-approved pot, Saxon said, it likely won’t be of sufficient quality to make a study worthwhile.

“It has been very difficult for researchers to obtain the product so that we can study what the impact is on actual patients,” he said, adding that it might not be strong enough to work as an effective pain-management alternative to an opiate.

“The research cannabis tends to be of somewhat lower potency.”

David Johnson, a spokesman for the state health department, noted, “there is a need for more epidemiological cannabis research.”

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