Potential harms from legalization of recreational cannabis use in Canada

  • Sarah B. Windle
  • Kristina Wade
  • Kristian B. Filion
  • Jonathan Kimmelman
  • Brett D. Thombs
  • Mark J. EisenbergEmail author


With the recent legalization of recreational cannabis use in Canada, questions remain concerning optimal regulation to minimize harms and ensure public health and safety. Patterns of use are subject to change following legalization, and it is important to consider the potential adverse effects that this may have on public health. Important areas of consideration are methods of consumption (e.g., vaping, edibles) and product proliferation; acute and long-term health and behavioural effects (including impaired driving); and use in vulnerable groups, such as children and youth, pregnant women, individuals with mental illness, individuals with low socio-economic status, and Indigenous populations. To support harm reduction measures and evidence-based policy, there is a need to anticipate the potential ramifications that legalization of recreational cannabis use may have on public health in Canada.


Cannabis Health legislation Public health Vulnerable populations 


L’usage récréatif du cannabis a été légalisé récemment au Canada, mais des questions demeurent sur la réglementation optimale pour réduire les préjudices et assurer la santé et la sécurité du public. Comme les tendances de consommation pourraient changer après la légalisation, il importe de tenir compte des éventuels effets indésirables que cela pourrait avoir sur la santé publique. Il faudra notamment considérer les méthodes de consommation (p. ex. vapotage, ingestion) et la prolifération des produits; les effets immédiats et à long terme sur la santé et les comportements (dont la conduite avec facultés affaiblies); ainsi que la consommation dans les groupes vulnérables comme les enfants et les jeunes, les femmes enceintes, les personnes atteintes de maladies mentales, les personnes de faible statut socioéconomique et les populations autochtones. Pour soutenir les mesures de réduction des méfaits et l’élaboration de politiques fondées sur les données probantes, il est nécessaire de prévoir les ramifications possibles de la légalisation de l’usage récréatif du cannabis sur la santé publique au Canada.


Cannabis Législation sanitaire Santé publique Populations vulnérables 



  1. Ashton, C. H. (2001). Pharmacology and effects of cannabis: a brief review. The British Journal of Psychiatry : the Journal of Mental Science, 178, 101–106.CrossRefGoogle Scholar
  2. Carliner, H., Brown, Q. L., Sarvet, A. L., & Hasin, D. S. (2017). Cannabis use, attitudes, and legal status in the U.S.: a review. Preventive Medicine.Google Scholar
  3. Colorado Department of Public Health & Environment. (2016). Monitoring Health Concerns Related to Marijuana in Colorado: 2016. Accessed July 31, 2017 from:
  4. Degenhardt, L., Ferrari, A. J., Calabria, B., Hall, W. D., Norman, R. E., McGrath, J., et al. (2013). The global epidemiology and contribution of cannabis use and dependence to the global burden of disease: results from the GBD 2010 study. PLoS One, 8(10), e76635.CrossRefGoogle Scholar
  5. Dickson, B., Mansfield, C., Guiahi, M., Allshouse, A. A., Borgelt, L. M., Sheeder, J., et al. (2018). Recommendations from cannabis dispensaries about first-trimester cannabis use. Obstetrics and Gynecology, 131(6), 1031–1038.CrossRefGoogle Scholar
  6. Fergusson, D. M., Horwood, L. J., & Swain-Campbell, N. (2002). Cannabis use and psychosocial adjustment in adolescence and young adulthood. Addiction, 97(9), 1123–1135.CrossRefGoogle Scholar
  7. First Nations Information Governance Centre. (2010). Regional Health Survey 2008/10. Retrieved August 14, 2017 from:
  8. Foulds, J., Veldheer, S., & Berg, A. (2011). Electronic cigarettes (e-cigs): views of aficionados and clinical/public health perspectives. International Journal of Clinical Practice, 65(10), 1037–1042.CrossRefGoogle Scholar
  9. Hall, W., & Degenhardt, L. (2009). Adverse health effects of non-medical cannabis use. Lancet, 374(9698), 1383–1391.CrossRefGoogle Scholar
  10. Hall, W., & Solowij, N. (1998). Adverse effects of cannabis. Lancet, 352(9140), 1611–1616.CrossRefGoogle Scholar
  11. Hartman, R. L., & Huestis, M. A. (2013). Cannabis effects on driving skills. Clinical Chemistry, 59(3), 478–492.CrossRefGoogle Scholar
  12. Investing News Network. (2017). Health Canada Gets New Funding for Cannabis Campaign. Retrieved March 23, 2018 from:
  13. Khalsa, J. H., Genser, S., Francis, H., & Martin, B. (2002). Clinical consequences of marijuana. Journal of Clinical Pharmacology, 42(11 Suppl), 7s–10s.CrossRefGoogle Scholar
  14. Lev-Ran, S., Le Foll, B., McKenzie, K., George, T. P., & Rehm, J. (2013). Cannabis use and cannabis use disorders among individuals with mental illness. Comprehensive Psychiatry, 54(6), 589–598.CrossRefGoogle Scholar
  15. Meier, M. H., Caspi, A., Ambler, A., Harrington, H., Houts, R., Keefe, R. S., et al. (2012). Persistent cannabis users show neuropsychological decline from childhood to midlife. Proceedings of the National Academy of Sciences of the United States of America, 109(40), E2657–E2664.CrossRefGoogle Scholar
  16. Metz, T. D., & Stickrath, E. H. (2015). Marijuana use in pregnancy and lactation: a review of the evidence. American Journal of Obstetrics and Gynecology, 213(6), 761–778.CrossRefGoogle Scholar
  17. Moir, D., Rickert, W. S., Levasseur, G., Larose, Y., Maertens, R., White, P., et al. (2008). A comparison of mainstream and sidestream marijuana and tobacco cigarette smoke produced under two machine smoking conditions. Chemical Research in Toxicology, 21(2), 494–502.CrossRefGoogle Scholar
  18. National Academies of Sciences, Engineering, and Medicine. (2017). The health effects of cannabis and cannabinoids: The current state of evidence and recommendations for research. Washington, DC: The National Academies Press. Scholar
  19. O'Connor, M. (2018). Medicinal cannabis in pregnancy - panacea or noxious weed? Journal of Law and Medicine, 25(3), 634–646.Google Scholar
  20. O'Kane, C. J., Tutt, D. C., & Bauer, L. A. (2002). Cannabis and driving: a new perspective. Emergency Medicine (Fremantle, WA), 14(3), 296–303.CrossRefGoogle Scholar
  21. Ramaekers, J. G., Berghaus, G., van Laar, M., & Drummer, O. H. (2004). Dose related risk of motor vehicle crashes after cannabis use. Drug and Alcohol Dependence, 73(2), 109–119.CrossRefGoogle Scholar
  22. Schauer, G. L., King, B. A., Bunnell, R. E., Promoff, G., & McAfee, T. A. (2016). Toking, vaping, and eating for health or fun: marijuana use patterns in adults, U.S, 2014. American Journal of Preventive Medicine, 50(1), 1–8.CrossRefGoogle Scholar
  23. Statistics Canada. (2018). National Cannabis Survey, first quarter 2018. Retrieved October 29, 2018 from:
  24. Substance Abuse and Mental Health Services Administration. (2016). Comparison of 2008–2009 and 2015–2016 NSDUH State Prevalence Estimates. Retrieved October 29, 2018 from:
  25. The Society of Obstetricians and Gynaecologists of Canada (SOGC). (2018). The SOGC Urges Canadians to Avoid Cannabis Use During Pregnancy and Breastfeeding. Retrieved April 30, 2018 from:
  26. United Nations Office on Drugs and Crime. (2006). Review of the world cannabis situation. Bulletin on Narcotics; LVIII (1–2).Google Scholar

Copyright information

© The Canadian Public Health Association 2019

Authors and Affiliations

  1. 1.Lady Davis InstituteJewish General HospitalMontrealCanada
  2. 2.Departments of Medicine and of Epidemiology, Biostatistics and Occupational HealthMcGill UniversityMontrealCanada
  3. 3.Biomedical Ethics UnitMcGill UniversityMontrealCanada
  4. 4.Departments of Psychiatry, of Psychology, and of Educational and Counselling PsychologyMcGill UniversityMontrealCanada
  5. 5.Division of Cardiology, Jewish General HospitalMcGill UniversityMontrealCanada

Personalised recommendations