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Mental Health and Legal Cannabis in Canada

As of today (Oct. 17), the recreational use of cannabis is now legal in Canada. Canada joins Uruguay, the first country to have legalized cannabis, and several U.S. states in taking a public health approach to manage cannabis production and use. In legalizing cannabis, the Government of Canada is taking a bold step in ending the criminalization of people who use cannabis, lessening the burden on the courts, blunting the impact of organized crime, and improving the health of Canadians by regulating and enhancing the quality and safety of the cannabis products they are consuming.

After alcohol, cannabis is the most widely used psychoactive substance in Canada.[i] It is consumed by Canadians for a variety reasons: for medical purposes, for pleasure, to relax, to experiment, and to cope with stress. Under the new Cannabis Act, adults 18 and older (or 19 in most provinces and territories) will now be able to possess up to 30 grams of legal cannabis bought from a provincially-licensed retailer, grow up to four cannabis plants for personal use, and make cannabis products at home.[ii] In addition to these federal regulations, individual provinces and territories have set further regulations regarding its purchase and consumption that are specific to each jurisdiction.

Although cannabis is now a legally regulated substance, its use still comes with risks. Like alcohol or tobacco, the use of cannabis engenders potential short and long-term health consequences. Cannabis use may cause acute psychotic symptoms and cognitive impairment similar to schizophrenia;[iii] it can increase the risk of accidents and injuries and is thought to be linked to reproductive and respiratory problems.[iv] For youth in particular, the risks for negative health consequences may be higher due to the potential for harm that cannabis use can have on the developing brain.[v] Furthermore, people who become heavy cannabis consumers may develop substance dependence, mental health problems, and/or a cannabis use disorder (CUD).[vi]

It is important to note that the legalization of recreational cannabis has not changed the current regime for medical cannabis access. In Canada, cannabis has been approved for medical use since 2001, which means that a physician can prescribe medical cannabis for any condition they believe it will aid.[vii] Some patients with chronic illnesses such as epilepsy, cancer, and chronic pain have found cannabis to be a beneficial medication for treating their symptoms.[viii] However, the stigma associated with cannabis use and concerns surrounding its safety and efficacy continue to prevent many physicians from prescribing cannabis to patients who may potentially benefit from its use.[ix]

At this time, there is not enough conclusive research on the harms and possible benefits of cannabis for both physical and mental health.[x] Given the uncertainties of cannabis use on health, CMHA hopes to see greater investments in research to establish more conclusive evidence on the harms and benefits of cannabis consumption over the life course and its impact on mental health for Canadians from diverse walks of life.

As recommended by Health Canada, Canadians should speak with a medical or public health professional if they are interested in more information on cannabis use and how it can affect their health.[xi] For those who choose to use cannabis recreationally, we recommend consulting Canada’s Lower-risk Cannabis Use Guidelines (LRCUG), which offer recommendations for reducing the harms associated with the consumption of cannabis.[xii]

CMHA commends the Government of Canada for being a leader on the international stage by taking a public health approach to manage cannabis use. The Government announced last year that it would invest $46 million in cannabis public education and awareness activities for Canadians, with targeted prevention efforts for youth. As there is a possibility that legalization may lead to a higher number of Canadians experiencing problematic cannabis use, we strongly recommend that the government also invest in treatment. Investments in treatment can be supported by an intelligently designed revenue plan that dedicates a significant percentage of revenue from cannabis or cannabis-related sales to public awareness campaigns, community resources, and research that support cannabis consumers experiencing mental health or substance use problems. With legalization, safeguarding the health and well-being of Canadians is paramount.

[i] “Canadian Alcohol and Drug Use Monitoring Survey: Summary Results for 2012,” Government of Canada, April 8, 2014,

[ii] “Cannabis Legalization and Regulation,” Government of Canada, October 11, 2018,

[iii] Hall, Wayne, “What has research over the past two decades revealed about the adverse health effects of recreational cannabis use?” Addiction 110 (2015): 30.

[iv] Fischer, Benedikt, Cayley Russell., Pamela Sabioni, Wim van den Brink, Bernard Le Foll, Wayne Hall., Jürgen Rehm and Robin Room, 10 Ways to Reduce Risks to Your Health When Using Cannabis: Canada’s Lower-Risk Cannabis Use Guidelines (LRCUG), 2018,

[v] Crépault, Jean‐François, Cannabis Policy Framework (Toronto, ON: Centre for Addiction and Mental Health, 2014), 5.

[vi] Le Foll, Bernard. “Is Cannabis Addictive?” In The Effects of Cannabis Use During Adolescence, edited by Tony George and Franco Vaccaroni, 48-61, Ottawa, ON: Canadian Centre on Substance Abuse, 2015.

[vii] Samoilov, Lucy and Claire P. Browne, “The Role of Medical Cannabis in the Opioid Crisis,” University of Western Ontario Medical Journal 87.1 (2018): 38.

[viii] Kalant, Harold and Amy J. Porath-Waller, Clearing the Smoke on Cannabis: Medical Use of Cannabis and Cannabinoids—An Update (Ottawa, ON: Canadian Centre on Substance Abuse, 2016), 1-20.

[ix] Juurlink, David N., “Medicinal Cannabis: Time to Lighten Up?” CMAJ 186.12 (2014): 897.

[x] Beirness, Douglas J., Harold Kalant, Opal A. McInnis, Darryl Plecas, and Amy J. Porath-Waller, Clearing the Smoke on Cannabis: Highlights – An Update (Ottawa, ON: Canadian Centre on Substance Abuse, 2016), 5; Couskin, Janna, Adrián E. Núñez, and Francesca M. Filbey, “Time to Acknowledge the Mixed Effects of Cannabis on Health: A Summary and Critical Review of the NASEM 2017 Report on the Health Effects of Cannabis and Cannabinoids,” Addiction 113.5 (2018).

[xi] Government of Canada, Does Cannabis Use Increase the Risk of Developing Psychosis or Schizophrenia? Cannabis Resource Series (Ottawa, On: Minister of Health, 2018).

[xii] Fischer, Benedikt, Cayley Russell., Pamela Sabioni, Wim van den Brink, Bernard Le Foll, Wayne Hall., Jürgen Rehm and Robin Room, “Lower-Risk Cannabis Use Guidelines (LRCUG): An evidence-based update,” American Journal of Public Health 107.8 (2017).
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