Opioid Resource Center

Opioid Resource Center

April 02, 2018
4 min read

Legalizing medical marijuana may aid in opioid crisis

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States that implemented medical marijuana laws showed reductions in opioid prescribing rates in high-risk Medicare and Medicaid Part D populations, according to two new studies published in JAMA Internal Medicine.

“Overprescribing of opioids is considered a major driving force behind the opioid epidemic in the United States,” Hefei Wen, PhD, from the University of Kentucky College of Public Health, and Jason M. Hockenberry, PhD, from Emory University Rollins School of Public Health, wrote.

“Marijuana is one of the potential nonopioid alternatives that can relieve pain at a relatively lower risk of addiction and virtually no risk of overdose. Marijuana liberalization, including medical and adult-use marijuana laws, has made marijuana available to more Americans,” they added.

Wen and Hockenberry performed a cross-sectional study to determine whether states that implemented medical and adult-use marijuana laws between 2011 and 2016 had reduced opioid prescribing rates and spending among Medicaid enrollees compared with states with no marijuana laws. The researchers defined the opioid prescribing rate as the number of opioid prescriptions that were mainly used for treating pain that was covered by Medicaid on a quarterly, per-1,000-Medicaid-enrollee basis.

States that implemented medical marijuana laws showed reductions in opioid prescribing rates in high-risk Medicare and Medicaid Part D populations.
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Data showed that opioid prescribing rates were 5.88% (95% CI, 11.55% to approximately 0.21%) lower in states that implemented medical marijuana laws and 6.38% (95% CI, 12.20% to approximately 0.56%) lower in states that implemented adult-use marijuana laws.

Additionally, Medicaid spending on prescription opioids was 9.78% (95% CI, 18.29% to approximately 1.26%) lower in states that implemented adult-use marijuana laws, correlating with $1,815 in annual savings in Medicaid spending per 1,000 enrollees.

“These findings suggest that medical and adult-use marijuana laws have the potential to reduce opioid prescribing for Medicaid enrollees, a segment of population with disproportionately high risk for chronic pain, opioid use disorder, and opioid overdose,” Wen and Hockenberry concluded. “Nonetheless, marijuana liberalization alone cannot solve the opioid epidemic. As with other policies evaluated in the previous literature, marijuana liberalization is but one potential aspect of a comprehensive package to tackle the epidemic.”

In another study Ashley C. Bradford, BA, from the University of Georgia, and colleagues conducted an analysis to determine whether implementation of state medical marijuana laws impacted opioid prescribing patterns in Medicare Part D from 2010 to 2015. For each state, the researchers measured the number of daily opioid doses prescribed in millions.

Results indicated that on average, states had 23.08 million daily doses of any opioid dispensed under Medicare Part D each year. In states with a medical marijuana laws, fewer daily doses of any opioid were filled.


When accounting for the type of medical marijuana law, statistically significant associations between the laws and any opioid prescribing were observed. There were 3.742 million fewer daily doses filled (95% CI, 6.289 to 1.194) in states with active dispensaries and 1.792 million fewer filled daily doses (95% CI, 3.532 to 0.052) in states with home-cultivation-only medical marijuana laws.

Home-cultivation-only-based medical marijuana laws were associated with 1.256 million fewer daily doses (95% CI, 2.319 to 0.193) of hydrocodone. Additionally, dispensary-based medical marijuana laws were associated with a reduction in the use of hydrocodone by 2.320 million daily doses filled (95% CI, 3.782 to 0.859) and the use of morphine by 0.361 million daily doses (95% CI, 0.718 to 0.005).

“Combined with previously published studies suggesting cannabis laws are associated with lower opioid mortality, these findings further strengthen arguments in favor of considering medical applications of cannabis as one tool in the policy arsenal that can be used to diminish the harm of prescription opioids,” Bradford and colleagues concluded.

In an accompanying editorial, Kevin P. Hill, MD, MHS, from Harvard Medical School and Beth Israel Deaconess Medical Center, and Andrew J. Saxon, MD, from the Center of Excellence in Substance Abuse Treatment and Education, wrote that the studies by Wen and Bradford contain critical limitations.

They point out that their studies are ecologic analyses and therefore do not confirm if patients avoided or reduced opioid use because they had greater access to medical marijuana. They also note that many factors, such as racial composition, educational attainment, prevalence of disease, disability and suicide rates, could have impacted the association between medical marijuana laws and opioid use.

Still, these two studies build upon past research that showed that patients who initiated medical marijuana for chronic pain demonstrated a reduced need for opioids, Hill and Saxon wrote.

“For many reasons, ranging from significant barriers to research on cannabis and cannabinoids to impatience, cannabis policy has raced ahead of cannabis science in the United States,” Hill and Saxon concluded. “For science to guide policy, funding the aforementioned studies must be a priority at the federal and state level. Many companies and states (via taxes) are profiting from the cannabis industry while failing to support research at the level necessary to advance the science.”

“This situation has to change to get definitive answers on the possible role for cannabis in the opioid crisis, as well as the other potential harms and benefits of legalizing cannabis,” they added. – by Alaina Tedesco


Bradford AC, et al. JAMA Intern Med. 2018;doi:10.1001/jamainternmed.2018.0266.

Hill KP, Saxon AJ. JAMA Intern Med. 2018;doi:10.1001/jamainternmed.2018.0254.

Wen H, Hockenberry JM. JAMA Intern Med. 2018;doi:10.1001/jamainternmed.2018.1007.

Disclosure: All authors report no relevant financial disclosures.