Data on cannabis adverse reactions: Overview of annual reports

This section contains annual surveillance reports related to the reporting of adverse reactions (side effects) suspected of being associated with cannabis products from the legal, regulated market to Health Canada.

Adverse reaction data with respect to cannabis products are one of several important indicators of the impact of legalization and regulation of cannabis on the health and safety of Canadian consumers and the risks associated with the real-world use of these products.

Health Canada conducts near-time monitoring, detection, and assessment of cases of adverse reactions involving cannabis products as part of the Vigilance Framework for Cannabis Products in Canada. Health Canada also monitors cases involving cannabis as a substance for broader issues of public health importance such as vaping-associated lung illness, cases involving pediatric populations from studies like the study on serious and life-threatening events associated with non-medical (recreational) cannabis use in Canadian children and youth, and other potential emerging safety issues (for example, potential drug interactions, like cannabis and warfarin). Adverse reaction data are often used in combination with other sources of data (for example, published literature, hospitalization data and survey data) to better understand cannabis use behaviours among Canadian consumers and their potential risks.

The purpose of these annual surveillance reports is to provide a descriptive analysis of the types of adverse reaction reports involving cannabis products regulated under the Cannabis Act and its Regulations that are received by Health Canada to address gaps in current knowledge about the risks associated with use of cannabis products for medical and non-medical purposes. These annual surveillance reports are intended for use by a broad range of stakeholders such as licence holders, health care professionals, the public and others, including regulators, poison control centres, provincial and territorial stakeholders, and researchers.

The annual surveillance reports present data on:

• mandatory and spontaneous serious adverse reaction reports associated with legal and regulated cannabis products received from licence holders
• voluntary and spontaneous non-serious adverse reactions reports associated with legal and regulated cannabis products received from licence holders
• voluntary and spontaneous serious and non-serious adverse reactions reports associated with legal and regulated cannabis products received from other reporters, including consumers, patients, healthcare professionals, medical cannabis clinics and provincial and territorial authorised retailers
• solicited reports (voluntary or mandatory) from studies (observational or interventional, excluding clinical trials)

There are several considerations to be aware of when interpreting data in these annual surveillance reports:

• The adverse reaction data presented in these reports are not reflective of the incidence of adverse reactions to cannabis products or the prevalence of cannabis consumption in the general Canadian population. This is in part due to the spontaneous mechanism through which adverse reaction data are reported to Health Canada; they are reflective of reports submitted to Health Canada and are subject to underreporting, variable reporting and misclassification.
• These annual surveillance reports focus on adverse reactions associated with legal and regulated cannabis products. Adverse reactions arising from cannabis from illegal or unidentifiable sources are generally excluded from these surveillance reports.
• Serious adverse reactions have a greater representation in the cannabis adverse reaction dataset as licence holders have a regulatory obligation to report these to Health Canada under Section 248 of the Cannabis Regulations. The submission of non-serious adverse reactions by license holders to Health Canada is voluntary; therefore, these cases are likely underreported and underrepresented in the dataset.
• Not all adverse reaction reports are medically confirmed as they are based on information supplied by the reporter, who may not be a health care professional.
• These reports do not cover adverse reactions associated with health products, including drugs containing cannabis, which are regulated under the Food and Drugs Act and its Regulations.
• The inclusion of a particular report in the database does not necessarily mean that the suspected products caused it. Additional scientific investigations are required to establish a cause-and-effect relationship between a cannabis product and an adverse reaction.

For key findings across multiple years, visit Key findings: Cannabis-related side effects.

Additional cannabis surveillance resources

• Cannabis market data
• National cannabis survey
• Canadian cannabis survey
• Canada Vigilance online database
• Canadian alcohol and drugs survey
• Canadian community health survey
• Canadian tobacco and nicotine survey
• Canadian student tobacco, alcohol and drugs survey
• Compliance and enforcement of the Cannabis Act reports
• Canadian hospitals injury reporting and prevention program
• Canadian postsecondary education alcohol and drug use survey

Related information

• Personal use of cannabis
• Health effects of cannabis
• Cannabis laws and regulations
• Producing and selling cannabis
• List of licensed cultivators, processors and sellers of cannabis
• Cannabis adverse reaction reporting guide for licence holders