Journal of General Internal Medicine

, Volume 34, Issue 8, pp 1419–1426 | Cite as

Impact of Medical Marijuana Legalization on Opioid Use, Chronic Opioid Use, and High-risk Opioid Use

  • Anuj Shah
  • Corey J. Hayes
  • Mrinmayee Lakkad
  • Bradley C. MartinEmail author
Original Research



To determine the association of medical marijuana legalization with prescription opioid utilization.


A 10% sample of a nationally representative database of commercially insured population was used to gather information on opioid use, chronic opioid use, and high-risk opioid use for the years 2006–2014. Adults with pharmacy and medical benefits for the entire calendar year were included in the population for that year. Multilevel logistic regression analysis, controlling for patient, person-year, and state-level factors, were used to determine the impact of medical marijuana legalization on the three opioid use measures. Sub-group analysis among cancer-free adults and cancer-free adults with at least one chronic non-cancer pain condition in the particular year were conducted. Alternate regression models were used to test the robustness of our results including a fixed effects model, an alternate definition for start date for medical marijuana legalization, a person-level analysis, and a falsification test.


The final sample included a total of 4,840,562 persons translating into 15,705,562 person years. Medical marijuana legalization was found to be associated with a lower odds of any opioid use: OR = 0.95 (0.94–0.96), chronic opioid use: OR = 0.93 (0.91–0.95), and high-risk opioid use: OR = 0.96 (0.94–0.98). The findings were similar in both the sub-group analyses and all the sensitivity analyses. The falsification tests showed no association between medical marijuana legalization and prescriptions for antihyperlipidemics (OR = 1.00; CI 0.99–1.01) or antihypertensives (OR = 1.00; CI 0.99–1.01).


In states where marijuana is available through medical channels, a modestly lower rate of opioid and high-risk opioid prescribing was observed. Policy makers could consider medical marijuana legalization as a tool that may modestly reduce chronic and high-risk opioid use. However, further research assessing risk versus benefits of medical marijuana legalization and head to head comparisons of marijuana versus opioids for pain management is required.


opioids marijuana chronic opioid use medical marijuana legalization pain 



Data obtained for this project was supported by the Translational Research Institute (TRI), grant UL1TR000039. Dr. Hayes was supported by the Translational Training in Addiction [1T32 DA 022981].

Compliance with Ethical Standards

Conflict of Interest

Dr. Anuj Shah was a graduate student at the University of Arkansas for Medical Sciences the entire duration of time this study was conducted. Dr. Shah is now an employee of Pharmerit International which is a contract research organization which receives revenue from pharmaceutical companies. None of the research presented in this manuscript is in any way associated with Dr.Shah’s present employment. No conflict of interests exist for Dr. Corey Hayes. No conflict of interests exist for Miss Mrinmayee Lakkad. Bradley C. Martin receives royalties from TrestleTree, a healthcare coaching company, for the exclusive use of an opioid risk prediction tool that he and his colleagues developed.

Supplementary material

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ESM 1 (DOCX 17 kb)


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Copyright information

© Society of General Internal Medicine 2019

Authors and Affiliations

  • Anuj Shah
    • 1
  • Corey J. Hayes
    • 2
    • 3
  • Mrinmayee Lakkad
    • 2
  • Bradley C. Martin
    • 2
    Email author
  1. 1.Pharmerit InternationalBethesdaUSA
  2. 2.Division of Pharmaceutical Evaluation and Policy, Department of Pharmacy Practice, College of PharmacyUniversity of Arkansas for Medical SciencesLittle RockUSA
  3. 3.Division of Health Services Research, Psychiatric Research Institute, College of MedicineUniversity of Arkansas for Medical SciencesLittle RockUSA

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