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Medical Marijuana Reduces Opioid Overdoses in Some States

October 1, 2014
A new study has found that lower opioid overdose death rates were associated with implementation of state medical marijuana laws, although the reason why remains unclear.

Deaths from opioid overdoses has been a growing public health concern in the US.1,2 However, over a 10-year period, states that implemented medical marijuana laws had lower annual opioid overdose (both from prescription and illicit drug use) mortality rates than the states that did not—24.8% lower rates.3

Using data provided by the Centers for Disease Control and Prevention, researchers used linear time-series regression models to track associations between opioid overdose mortality rates and the presence of medical marijuana laws.The study looked at all 50 states from 1999 to 2010.4

They found that from the point of time when medical marijuana laws became active, referred to as "implementation," decreases in opioid overdose mortality rates strengthened with every subsequent year. They found that that marijuana laws associated with over 1,700 prevented deaths in 2010, alone.4

According to lead author Marcus Bachhuber, MD, from the Philadelphia Veterans Affairs Medical Center in Philadelphia, Pennsylvania, the results of this study were an important step in assessing the possible benefits of medical marijuana implementation.

"Ours is the first study, to our knowledge, that looked at this," said Dr. Bachhuber, "so it will be important to continue collecting information and updating these results."

Policy Decreases Mortality

The study used numerous analyses to make sure the results were not being influenced by other factors—such as suicide deaths, heroin use, unemployment status, hard-to-measure confounder variables, cardiovascular disease, septicemia, and even opioid analgesic policies.

Marie Hayes, from the University of Maine and the Eastern Maine Medical Center in Bangor, Maine, a co-author of an accompanying editorial on the research, said she thought the study was "striking" and an impressively extensive analysis, noting that "it's the first time that evidence of a policy like (medical marijuana) could actually decrease (analgesic) mortality."5

But while the JAMA study featured robust statistical analyses, both Dr. Bachhuber and Dr. Hayes stressed that the information isn't comprehensive enough to prove the association is causal. The study was limited by its vacancies in decedent medical histories, and the mechanism still is unclear as to why this association exists.

There are various proposed theories, however, such as pain patients using medical marijuana as an adjuvant or replacement medicine or illicit opioid users curbing their abuse with marijuana, but this is speculation.

"We need studies of individuals over time to really pinpoint how these laws might be shifting behavior," said Dr. Bachhuber.

Barriers to Medical Marijuana

There are still many barriers to the use of marijuana as an accepted form of pain medication, with some practitioners expressing concern over a lack of research into marijuana's effects,6 as well as the possible health risks from smoking the substance,7  and the noticeable neurological dangers it may present to the brain, especially in adolescents.8

"I think many medical providers struggle in figuring out what conditions medical marijuana could be used for, who would benefit from it, how effective it is, and who might have side effects," said Dr. Bachhuber. "Going forward, it will be important to update our results as more states pass medical marijuana laws and more information is out there."

While studies have shown marijuana could be used as an effective form of pain management,9-12 research into medical marijuana still is lacking.4

Furthermore, the complexity of state-wide implementations13 and the legal contention between state and federal jurisdictions over marijuana laws have kept it from undergoing FDA's rigorous Phase 3 testing, and the inability to patent Cannabis sativa, a natural plant, introduces additional complexities to its standardization. Some practitioners have feared repercussions for even considering the federally mandated Schedule I narcotic as a possible treatment.14

In a debate held during PAINWeek,  in Las Vegas in September, the audience was polled about what public policy should apply to medical marijuana. The consensus from the audience of pain specialist is that the Drug Enforcement Agency should reschedule marijuana as a Schedule II drug, down from a Schedule 1, so that universities and medical companies can obtain products to properly study.

"We would know more if we funded [medical marijuana research]" said Dr. Hayes. And while medical marijuana dispensaries do follow guidelines created by the American Herbal Product Association (AHPA) and standards set by American Herbal Pharmacopoeia (AHP), she said that medical marijuana warrants a safe format for it to be widely supported by medical care providers.

"That's what we're worried about: How can we deliver [medical marijuana] safely," and in a standardized format, Dr. Hayes said. "I think that would make everybody more comfortable with it as a medicine."

"If the relationship between medical cannabis laws and opioid analgesic overdose mortality is substantiated in further work, enactment of laws to allow for use of medical cannabis may be advocated as part of a comprehensive package of policies to reduce the population risk of opioid analgesics," Dr. Bachhuber and colleagues concluded.

Last updated on: May 17, 2016
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