Impacts of Medical Marijuana Laws on Young Americans Across the Developmental Spectrum
Introduction State legalization of marijuana for medical purposes could increase illicit marijuana use among young people. Medical marijuana laws may boost the availability of marijuana and reduce perceptions of its harmfulness, leading more young people to try it. Prior studies report little evidence that these laws are impacting marijuana consumption by young Americans, and none have systematically compared developmentally distinct age groups. Methods We performed multilevel, serial cross-sectional analyses on ten annual waves of U.S. National Survey on Drug Use and Health, from 2004 to 2013, comparing young people in states with and without medical marijuana laws. Disaggregated analyses compared multiple measures of marijuana use across approximately 450,300 individuals in early adolescence (12–14 years), late adolescence (15–17 years) and young adulthood (18–25 years). Results Dwelling in a state that had legalized medical marijuana was not associated with marijuana consumption in the past month among early adolescents, late adolescents or young adults. However, young adults living in medical marijuana states were significantly more likely to have initiated first use in the past year. Conclusions Medical marijuana laws increase the likelihood that young adults will start using marijuana but do not affect more vulnerable developmental groups in early and late adolescence. Delaying the age of first use into young adulthood can reduce the risk of a drug use disorder later in life. Young adults are in the peak years of engagement with illicit drugs and state medical marijuana laws appear to be leading larger numbers to try the drug.
KeywordsMarijuana Medical marijuana laws Development of substance abuse Adolescence Young adulthood
We would like to thank our colleagues who assisted in the data collection and technical execution of this manuscript, including Timothy Bates MA, Susan Chapman PhD, Casey Palmer MS, and Juliana Fung of the University of California at San Francisco. We would also like to acknowledge staff at the Substance Abuse and Mental Health Administration and the University of Michigan for their assistance in data acquisition and management. This study was supported by a grant from the U.S. National Institute on Drug Abuse (Grant No. R01 DA034091) but played no role in the design and conduct of the study; data collection, management, analysis, and interpretation of the data; or in the preparation of this manuscript.
Conflict of interest
All authors declare that they have no conflicts of interest.
- Anderson, D. M., Hansen, B., & Rees, D. I. (2012). Medical marijuana laws and teen marijuana use. American Law and Economics Review, 17(2), 495–528.Google Scholar
- Babor, T., Brown, J., & Boca, F. D. (1990). Validity of self-reports in applied research on addictive behaviors: Fact or fiction? Behavioral Assessment, 12, 5–31.Google Scholar
- Babor, T. F., Edwards, P. C. J., Fischer, G., Foxcroft, B., Humphreys, D. R., Reuter, K., P (2010). Drug Policy and the Public Good. New York: Oxford University Press.Google Scholar
- Hasin, D. S., Wall, M., Keyes, K. M., Cerdá, M., Schulenberg, J., O’Malley, P. M., et al.(2015). Medical marijuana laws and adolescent marijuana use in the usa from 1991 to 2014: Results from annual, repeated cross-sectional surveys. The Lancet Psychiatry, 2(7), 601–608. https://doi.org/10.1016/S2215-0366(15)00217-5.CrossRefPubMedPubMedCentralGoogle Scholar
- Johnston, L. D., O’Malley, P. M., & Bachman, J. G. (2016). Monitoring The Future National Survey Results On Drug Use,1975–2015: Overview, Key Findings On Adolescent Drug Use. Ann Arbor.Google Scholar
- Krupnick, M. (2016). High times and agency unite to sell marijuana to mainstream, The New York Times. Retrieved from http://www.nytimes.com/2016/05/02/business/media/high-times-and-agency-unite-to-sell-marijuana-to-mainstream.html?_r=3.
- Meier, M. H., Caspi, A., Ambler, A., Harrington, H., Houts, R., Keefe, R. S. E., et al. (2012). Persistent cannabis users show neuropsychological decline from childhood to midlife. Proceedings of the National Academy of Sciences, 109(40). https://doi.org/10.1073/pnas.1206820109.
- National Survey on Drug Use and Health. (2011). Person-Level Sampling Weight Calibration. Maryland: Rockville.Google Scholar
- Nussbaum, A. M., Thurstone, C., McGarry, L., Walker, B., & Sabel, A. L. (2015). Use and diversion of medical marijuana among adults admitted to inpatient psychiatry. The American Journal of Drug and Alcohol Abuse, 41, 166–172. https://doi.org/10.3109/00952990.2014.949727.CrossRefPubMedGoogle Scholar
- POLIDATA. Demographic & political guides: Political data analysis. http://www.polidata.org.
- Rogers, W. (1993). Quantile regression standard errors. Stata Technical Bulletin, 2(9).Google Scholar
- Room, R., Fischer, B., Hall, W., Lenton, S., & Reute, P. (2010). Cannabis policy: Moving beyond stalemate. New York: Oxford University Press.Google Scholar
- SAMHDA. (2011). National survey on drug use and health, 2011. Ann Arbor, MI: SAMHDA.Google Scholar
- StataCorp. (2015). Stata statisitical software: Release 14. College station. TX: StataCorp LP.Google Scholar
- Stuart, E. A., & Green, K. M. (2008). Using full matching to estimate causal effects in nonexperimental studies: Examining the relationship between adolescent marijuana use and adult outcomes. Developmental Psychology, 44(2), 395–406. https://doi.org/10.1037/0012-16188.8.131.525.CrossRefPubMedPubMedCentralGoogle Scholar
- Substance Abuse and Mental Health Services Administration. (2016). Youth Perception of Marijuana Harm Decreases as “710” Becomes More Potent. http://newsletter.samhsa.gov/2016/05/25/710-oil-risks/.
- The Office of Environmental Health Hazard Assessment. (2009). Health and safety code sect. 25249.8(b) and title 27, cal code of regs., Sect. 25302 et seq.A. Availability of Hazard Identification Materials for Marijuana Smoke. Retrieved April 2, 2017 from http://oehha.ca.gov/proposition-65/crnr/availability-hazard-identification-materials-marijuana-smoke.
- Wen, H., Hockenberry, J. M., & Ciummings, J. R. (2014). The Effect of Medical Marijuana Laws on Marijuana, Alcohol, and Hard Drug Use. National Bureau of Economic Research Working Paper Series, No. 20085.Google Scholar
- Wooldridge, J. M. (2002). Econometric analysis of cross section and panel data. Cambridge: MIT Press.Google Scholar