The Challenges of Projecting the Public Health Impacts of Marijuana Legalization in Canada; Comment on “Legalizing and Regulating Marijuana in Canada: Review of Potential Economic, Social, and Health Impacts”

Document Type: Commentary

Authors

1 British Columbia Centre for Excellence in HIV/AIDS, St. Paul’s Hospital, Vancouver, BC, Canada

2 School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada

3 Department of Medicine, University of British Columbia, St. Paul’s Hospital, Vancouver, BC, Canada

Abstract

A recent editorial in this journal provides a summary of key economic, social, and public health considerations of the forthcoming legislation to legalize, regulate, and restrict access to marijuana in Canada. As our government plans to implement an evidence-based public health framework for marijuana legalization, we reflect and expand on recent discussions of the public health implications of marijuana legalization, and offer additional points of consideration. We select two commonly cited public concerns of marijuana legalization – adolescent usage and impaired driving – and discuss how the underdeveloped and equivocal body of scientific literature surrounding these issues limits the ability to predict the effects of legalization. Finally, we discuss the potential for some potential public health benefits of marijuana legalization – specifically the potential for marijuana to be used as a substitute to opioids and other risky substance use – that have to date not received adequate attention.

Keywords

Main Subjects


 
  1. Hajizadeh M. Legalizing and regulating marijuana in Canada: review of potential economic, social, and health impacts. Int J Health Policy Manag. 2016;5(8):453-456. doi:10.15171/ijhpm.2016.63
  2. Di Forti M, Marconi A, Carra E, et al. Proportion of patients in south London with first-episode psychosis attributable to use of high potency cannabis: a case-control study. Lancet Psychiatry. 2015;2(3):233-238. doi:10.1016/S2215-0366(14)00117-5
  3. Di Forti M, Iyegbe C, Sallis H, et al. Confirmation that the AKT1 (rs2494732) genotype influences the risk of psychosis in cannabis users. Biol Psychiatry. 2012;72(10):811-816. doi:10.1016/j.biopsych.2012.06.020
  4. French L, Gray C, Leonard G, et al. Early cannabis use, polygenic risk score for schizophrenia and brain maturation in adolescence. JAMA Psychiatry. 2015;72(10):1002-1011. doi:10.1001/jamapsychiatry.2015.1131
  5. Power RA, Verweij KJ, Zuhair M, et al. Genetic predisposition to schizophrenia associated with increased use of cannabis. Mol Psychiatry. 2014;19(11):1201-1204. doi:10.1038/mp.2014.51
  6. Cheetham A, Allen NB, Whittle S, Simmons JG, Yucel M, Lubman DI. Orbitofrontal volumes in early adolescence predict initiation of cannabis use: a 4-year longitudinal and prospective study. Biol Psychiatry. 2012;71(8):684-692. doi:10.1016/j.biopsych.2011.10.029
  7. Rogeberg O. Correlations between cannabis use and IQ change in the Dunedin cohort are consistent with confounding from socioeconomic status. Proc Natl Acad Sci U S A. 2013;110(11):4251-4254. doi:10.1073/pnas.1215678110
  8. Mokrysz C, Landy R, Gage SH, Munafò MR, Roiser JP, Curran HV. Are IQ and educational outcomes in teenagers related to their cannabis use? A prospective cohort study. J Psychopharmacol. 2016;30(2):159-168. doi:10.1177/0269881115622241
  9. Jackson NJ, Isen JD, Khoddam R, et al. Impact of adolescent marijuana use on intelligence: Results from two longitudinal twin studies. Proc Natl Acad Sci USA. 2016;113(5):E500-508. doi:10.1073/pnas.1516648113
  10. Canadian Centre on Substance Abuse (CCSA). Clearing the Smoke on Cannabis. http://www.ccsa.ca/Resource%20Library/CCSA-Clearing-Smoke-on-Cannabis-Highlights-2015-en.pdf. Published April 2015.
  11. Summary of results of the Youth Smoking Survey 2012-2013. Canada: Government of Canada; 2014.
  12. Child well-being in rich countries: a comparative overview. Florence: UNICEF; 2013.
  13. Ubelacker S. Pot should be legalized, regulated and sold like alcohol: addiction centre. The Globe and Mail. October 9, 2014. http://www.theglobeandmail.com/life/health-and-fitness/health/pot-should-be-legalized-regulated-and-sold-like-alcohol-addiction-centre/article20995728/.
  14. Spithoff S, Kahan M. Cannabis and Canadian youth: evidence, not ideology. Can Fam Physician. 2014;60(9):785-787.
  15. Marijuana. Liberal Party of Canada website. https://www.liberal.ca/realchange/marijuana/. Accessed July 5, 2016. Published 2015.
  16. Hasin DS, Wall M, Keyes KM, et al. Medical marijuana laws and adolescent marijuana use in the USA from 1991 to 2014: results from annual, repeated cross-sectional surveys. Lancet Psychiatry. 2015;2(7):601-608. doi:10.1016/s2215-0366(15)00217-5
  17. Choo EK, Benz M, Zaller N, Warren O, Rising KL, McConnell KJ. The impact of state medical marijuana legislation on adolescent marijuana use. J Adolesc Health. 2014;55(2):160-166. doi:10.1016/j.jadohealth.2014.02.018
  18. Hall W, Solowij N. Adverse effects of cannabis. Lancet. 1998;352(9140):1611-1616. doi:10.1016/S0140-6736(98)05021-1
  19. Rogeberg O, Elvik R. The effects of cannabis intoxication on motor vehicle collision revisited and revised. Addiction. 2016. doi:10.1111/add.13347
  20. National Institute on Drug Abuse. Marijuana: Facts for Teens. http://www.drugabuse.gov/publications/marijuana-facts-teens/want-to-know-more-some-faqs-about-marijuana. Accessed July 5, 2016. Published 2013.
  21. Salomonsen-Sautel S, Min SJ, Sakai JT, Thurstone C, Hopfer C. Trends in fatal motor vehicle crashes before and after marijuana commercialization in Colorado. Drug Alcohol Depend. 2014;140:137-144. doi:10.1016/j.drugalcdep.2014.04.008
  22. Rocky Mountain High Intensity Drug Trafficking Area. The Legalization of Marijuana in Colorado: The Impact. August2014.
  23. Nutt DJ, King LA, Phillips LD. Drug harms in the UK: a multicriteria decision analysis. Lancet. 2010;376(9752):1558-1565. doi:10.1016/s0140-6736(10)61462-6
  24. Bachhuber MA, Saloner B, Cunningham CO, Barry CL. Medical cannabis laws and opioid analgesic overdose mortality in the United States, 1999-2010. JAMA Intern Med. 2014. doi:10.1001/jamainternmed.2014.4005
  25. Lau N, Sales P, Averill S, Murphy F, Sato S-O, Murphy S. A safer alternative: Cannabis substitution as harm reduction. Drug Alcohol Rev. 2015;34(6):654-659. doi:10.1111/dar.12275
  26. Lucas P, Reiman A, Earleywine M, et al. Cannabis as a substitute for alcohol and other drugs: A dispensary-based survey of substitution effect in Canadian medical cannabis patients. Addiction Res Theory. 2013;21(5):435-442. doi:10.3109/16066359.2012.733465
  27. Lucas P, Walsh Z, Crosby K, et al. Substituting cannabis for prescription drugs, alcohol and other substances among medical cannabis patients: The impact of contextual factors. Drug Alcohol Rev. 2015. doi:10.1111/dar.12323