While the impacts of cannabis on public health are significantly lower than those of tobacco and alcohol, cannabis consumption is not without risks, especially if used frequently or if use begins earlier in life. 1 Frequent use of cannabis (typically defined as daily or near-daily use) is associated with health complications, including mild impairments to memory, attention, and other cognitive functions, especially the younger a person begins to consume it. And those who start using cannabis early and use it frequently are at risk of having negative impacts later in life. 2
An additional health risk is associated with the consumption of burned cannabis. Smoking is the most hazardous method of cannabis use, and can cause respiratory health problems, such as cough, wheeze, worsening of asthma symptoms, sore throat, chest tightness, and shortness of breath. 3 Alternatives (such as vaporizers or edibles) are not risk-free, but they can reduce the risks associated with smoking cannabis. For more information about lower-risk practices see sub-section 5. 4
In adolescence and early adulthood, the brain goes through a maturation process that includes refinements and reorganization of the brain’s circuitry. Cannabis use can negatively affect this process. 5 Those who start using cannabis early (such as in adolescence) are at higher risk of harm. 2 Although there is not enough evidence of a cause-and-effect relationship, early and frequent use of cannabis is a risk factor for developing mental illness, including psychosis. 6 For more information about these links see Section 2.
Driving under the influence of substances, including cannabis, contributes to fatal road crashes and, in Canada, young people are the largest group of drivers in fatal car crashes who test positive for drugs. 7 Young Canadians (ages 15–24) were more than twice as likely as older Canadians to report driving after using cannabis. 8 In 2017, a Health Canada survey showed that many people are unaware of the potential risks of cannabis-impaired driving. 9 While significant steps have been made to inform young adults in Canada about the harms of drinking and driving, students in Ontario were more likely to report driving after using cannabis than driving after drinking. 10 Campus messaging and harm reduction initiatives should provide accurate information and education regarding the risks of driving after using cannabis.
Given the high rates of cannabis use among youth and the concerns related to the effects of cannabis on brain development and driving ability, youth are a priority population that needs targeted health promotion interventions and messaging.
References
- Centre for Addiction and Mental Health. (2014). Cannabis Policy Framework. Retreived From: https://www.camh.ca/en/camh-news-and-stories/to-2016/camhs-cannabis-policy-framework-legalization-with-regulation[↩]
- George, T., & Vaccarino, F. (Eds.). (2015). Substance abuse in Canada: The Effects of Cannabis Use during Adolescence. Ottawa, ON: Canadian Centre on Substance Abuse.[↩][↩]
- McInnis, O., & Plecas, D. (2017). Clearing the Smoke on Cannabis. Respiratory effects of Cannabis Smoking. Canadian Centre for Substance Abuse. Retrieved from: http://www.ccdus.ca/Resource%20Library/CCSA-Cannabis-Use-Respiratory-Effects-Report-2016-en.pdf[↩]
- Fischer, B., Russell, C., Sabioni, P., van den Brink, W., Le Foll, B., Hall, W. et al. (2017). Lower-risk cannabis use guidelines (LRCUG): An evidence-based update. American Journal of Public Health, 107(8).[↩]
- Canadian Psychiatric Association. (2017). Implications of Cannabis Legalization on Youth and Young Adults. Retreived from: https://www.cpa-apc.org/wp-content/uploads/Cannabis-Academy-Position-Statement-ENG-FINAL-no-footers-web.pdf[↩]
- Ben Amar M, Potvin S .(2007). Cannabis and Psychosis: What is the Link? Journal of Psychoactive Drugs; 39 (2), 131-42[↩]
- Health Canada. (2018). Drug Impaired Driving. Retrieved from: https://www.canada.ca/en/services/policing/police/community-safety-policing/impaired-driving/drug-impaired-driving.html[↩]
- Canadian Centre for Substance Use and Addiction. (2018). Impaired Driving in Canada. Retrieved from: http://www.ccdus.ca/Resource%20Library/CCSA-Impaired-Driving-Canada-Summary-2018-en.pdf[↩]
- Health Canada (2017). Canadian Cannabis Survey — 2017 summary. Retrieved from: www.canada.ca/en/healthcanada/services/publications/drugs-health-products/canadian-cannabis-survey-2017-summary.html[↩]
- Boak, A., Hamilton, H. A., Adlaf, E. M., & Mann, R. E., (2017). Drug use among Ontario students, 1977-2015: Detailed OSDUHS findings (CAMH Research Document Series No. 46). Toronto, Ont.: Centre for Addiction and Mental Health.[↩]
