Is enactment of medical marijuana laws in the United States associated with changes in nonmedical prescription opioid use and prescription opioid use disorder among prescription opioid users overall and by age and racial/ethnic group?
This cross-sectional study using individual-level restricted data from the 2004 to 2014 US National Survey on Drug Use and Health showed small increases in nonmedical prescription opioid use and no significant change in prescription opioid use disorder among users after medical marijuana law enactment. Similar patterns were observed across age and racial/ethnic groups.
Medical marijuana law enactment was not associated with a reduction in individual-level nonmedical prescription opioid use, contradicting the hypothesis that people would substitute marijuana for prescription opioids.
Between 1997 and 2017, the United States saw increases in nonmedical prescription opioid use and its consequences, as well as changes in marijuana policies. Ecological-level research hypothesized that medical marijuana legalization may reduce prescription opioid use by allowing medical marijuana as an alternative.
To investigate the association of state-level medical marijuana law enactment with individual-level nonmedical prescription opioid use and prescription opioid use disorder among prescription opioid users and to determine whether these outcomes varied by age and racial/ethnic groups.
Design, Setting, and Participants
This cross-sectional study used restricted data on 627 000 individuals aged 12 years and older from the 2004 to 2014 National Survey on Drug Use and Health, a population-based survey representative of the civilian population of the United States. Analyses were completed from March 2018 to May 2018.
Time-varying indicator of state-level medical marijuana law enactment (0 = never law enactment, 1 = before law enactment, and 2 = after law enactment).
Main Outcomes and Measures
Past-year nonmedical prescription opioid use and prescription opioid use disorder among prescription opioid users. Odds ratios of nonmedical prescription opioid use and prescription opioid use disorder comparing the period before and after law enactment were presented overall, by age and racial/ethnic group, and adjusted for individual- and state-level confounders.
The study sample included 627 000 participants (51.51% female; 9.88% aged 12-17 years, 13.30% aged 18-25 years, 14.30% aged 26-34 years, 25.02% aged 35-49 years, and 37.50% aged ≥50 years; the racial/ethnic distribution was 66.97% non-Hispanic white, 11.83% non-Hispanic black, 14.47% Hispanic, and 6.73% other). Screening and interview response rates were 82% to 91% and 71% to 77%, respectively. Overall, there were small changes in nonmedical prescription opioid use prevalence after medical marijuana law enactment (4.32% to 4.86%; adjusted odds ratio, 1.13; 95% CI, 1.06-1.20). Prescription opioid use disorder prevalence among prescription opioid users decreased slightly after law enactment, but the change was not statistically significant (15.41% to 14.76%; adjusted odds ratio, 0.95; 95% CI, 0.81-1.11). Outcomes were similar when stratified by age and race/ethnicity.
Conclusions and Relevance
This study found little evidence of an association between medical marijuana law enactment and nonmedical prescription opioid use or prescription opioid use disorder among prescription opioid users. Further research should disentangle the potential mechanisms through which medical marijuana laws may reduce opioid-related harm.
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CME Disclosure Statement: Unless noted, all individuals in control of content reported no relevant financial relationships. If applicable, all relevant financial relationships have been mitigated.
Accepted for Publication: May 28, 2019.
Published: July 17, 2019. doi:10.1001/jamanetworkopen.2019.7216
Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2019 Segura LE et al. JAMA Network Open.
Corresponding Author: Silvia S. Martins, MD, PhD, Department of Epidemiology, Mailman School of Public Health, Columbia University, 722 W 168th St, Room 509, New York, NY 10032 (firstname.lastname@example.org).
Author Contributions: Dr Segura had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Concept and design: Segura, Philbin, Martins.
Acquisition, analysis, or interpretation of data: Segura, C. M. Mauro, Levy, Khauli, P. M. Mauro, Martins.
Drafting of the manuscript: Segura, Levy, Khauli.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Segura, C. M. Mauro, Levy.
Obtained funding: Martins.
Administrative, technical, or material support: Segura, Khauli, Philbin, Martins.
Supervision: Segura, Philbin, Martins.
Conflict of Interest Disclosures: Dr C. M. Mauro reported grants from the National Institute on Drug Abuse during the conduct of the study. Dr Martins reported grants from the National Institute on Drug Abuse, National Institutes of Health during the conduct of the study. No other disclosures were reported.
Funding/Support: Funding for this project was provided by grant K01DA039804A (Dr Philbin), grant K01DA045224 (Dr P. M. Mauro), and grant R01DA037866 (Dr Martins) from the National Institute on Drug Abuse, National Institutes of Health.
Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Disclaimer: The views expressed in this article are those of the authors and do not necessarily reflect those of the National Institute on Drug Abuse, National Institutes of Health.
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