Canada's Lower-Risk Cannabis Use Guidelines, based on a scientific review by an international team of experts and released with the endorsement of key medical and public health organisations, provide 10 science-based recommendations to enable cannabis users to reduce their health risks.
The guidelines address the fact that, despite the health risks of cannabis use, the rate of cannabis use in Canada is among the highest in the world. More than 10% of adults and 25% of adolescents report cannabis use over the past year. The health risks range from problems with memory and physical coordination, to motor vehicle accidents and mental health or dependence problems.
As Canada moves towards legalisation with the introduction of the federal Cannabis Act, it provides an opportunity not only to regulate the use and supply, but also to educate and inform cannabis users to prevent or reduce cannabis-related health problems.
"Factual, science-based information can provide guidance to cannabis users to make choices that reduce both immediate and long-term risks to their health," says Dr Benedikt Fischer, senior scientist at the Centre for Addiction and Mental Health (CAMH), who led the development of the guidelines. They are a project of the Ontario site of the Canadian Research Initiative on Substance Misuse (CRISM), a national initiative funded by the Canadian Institutes of Health Research.
"Cannabis use carries with it real health risks, and mitigating those risks for Canadians – particularly young Canadians – must be the first priority," says Dr Laurent Marcoux, president-elect of the Canadian Medical Association (CMA). "The CMA continues to recommend a broad public health policy approach focused on preventing problematic drug use; ensuring the availability of assessment and treatment services for those who wish to stop using; and harm reduction to increase the safety for those who are using."
While the first guideline recommendation is to abstain from cannabis use to avoid all risks, the remaining recommendations address the elevated potential of risks related to initiating use at a young age, high potency products, alternative delivery systems, heavy use and driving, as well as identifying people at higher risk of problems – with concrete recommendations for risk reduction in each case.
"These guidelines are an important tool supporting a public health approach to cannabis use," says Ian Culbert, executive director of the Canadian Public Health Association. "People who use cannabis and cannabis-derived products, front-line practitioners, and public health professionals can all benefit from having access to evidence-informed guidelines that can help reduce the potential negative health effects associated with cannabis use. Through their widespread adoption, the guidelines will provide people who use cannabis with the information they need to manage their use and protect their health and well-being."
The other organisations endorsing the guidelines are the Canadian Society of Addiction Medicine, the Canadian Centre on Substance Use and Addiction, and CAMH.
"Given the many people, especially young people, who use and may be harmed by cannabis use, we are pleased to recommend this evidence-based harm-reduction guidance to Canadians who do choose to use cannabis," says Dr David Allison, CMO of Health for Newfoundland and Labrador, speaking on behalf of the Council of Chief Medical Officers of Health. "This document is a welcome addition to our tool box for protecting and promoting the health of Canadians."
Using scientific evidence as the basis for public guidelines is similar to existing public health initiatives for low-risk drinking, or safer sexual behaviours to avoid infection or unwanted pregnancy.
In addition to the scientific paper, the guidelines are available as a public brochure for users and an evidence summary for health professionals.
Abstract
Background: Cannabis use is common in North America, especially among young people, and is associated with a risk of various acute and chronic adverse health outcomes. Cannabis control regimes are evolving, for example toward a national legalization policy in Canada, with the aim to improve public health, and thus require evidence-based interventions. As cannabis-related health outcomes may be influenced by behaviors that are modifiable by the user, evidence-based Lower-Risk Cannabis Use Guidelines (LRCUG)—akin to similar guidelines in other health fields—offer a valuable, targeted prevention tool to improve public health outcomes.
Objectives: To systematically review, update, and quality-grade evidence on behavioral factors determining adverse health outcomes from cannabis that may be modifiable by the user, and translate this evidence into revised LRCUG as a public health intervention tool based on an expert consensus process.
Search methods: We used pertinent medical search terms and structured search strategies, to search MEDLINE, EMBASE, PsycINFO, Cochrane Library databases, and reference lists primarily for systematic reviews and meta-analyses, and additional evidence on modifiable risk factors for adverse health outcomes from cannabis use.
Selection criteria: We included studies if they focused on potentially modifiable behavior-based factors for risks or harms for health from cannabis use, and excluded studies if cannabis use was assessed for therapeutic purposes.
Data collection and analysis: We screened the titles and abstracts of all studies identified by the search strategy and assessed the full texts of all potentially eligible studies for inclusion; 2 of the authors independently extracted the data of all studies included in this review. We created Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow-charts for each of the topical searches. Subsequently, we summarized the evidence by behavioral factor topic, quality-graded it by following standard (Grading of Recommendations Assessment, Development, and Evaluation; GRADE) criteria, and translated it into the LRCUG recommendations by the author expert collective on the basis of an iterative consensus process.
Main results: For most recommendations, there was at least “substantial” (i.e., good-quality) evidence. We developed 10 major recommendations for lower-risk use: (1) the most effective way to avoid cannabis use–related health risks is abstinence; (2) avoid early age initiation of cannabis use (i.e., definitively before the age of 16 years); (3) choose low-potency tetrahydrocannabinol (THC) or balanced THC-to-cannabidiol (CBD)–ratio cannabis products; (4) abstain from using synthetic cannabinoids; (5) avoid combusted cannabis inhalation and give preference to nonsmoking use methods; (6) avoid deep or other risky inhalation practices; (7) avoid high-frequency (e.g., daily or near-daily) cannabis use; (8) abstain from cannabis-impaired driving; (9) populations at higher risk for cannabis use–related health problems should avoid use altogether; and (10) avoid combining previously mentioned risk behaviors (e.g., early initiation and high-frequency use).
Authors’ conclusions: Evidence indicates that a substantial extent of the risk of adverse health outcomes from cannabis use may be reduced by informed behavioral choices among users. The evidence-based LRCUG serve as a population-level education and intervention tool to inform such user choices toward improved public health outcomes. However, the LRCUG ought to be systematically communicated and supported by key regulation measures (e.g., cannabis product labeling, content regulation) to be effective. All of these measures are concretely possible under emerging legalization regimes, and should be actively implemented by regulatory authorities. The population-level impact of the LRCUG toward reducing cannabis use–related health risks should be evaluated.
Public health implications: Cannabis control regimes are evolving, including legalization in North America, with uncertain impacts on public health. Evidence-based LRCUG offer a potentially valuable population-level tool to reduce the risk of adverse health outcomes from cannabis use among (especially young) users in legalization contexts, and hence to contribute to improved public health outcomes.
Authors
Benedikt Fischer, Cayley Russell, Pamela Sabioni, Wim van den Brink, Bernard Le Foll, Wayne Hall, Jürgen Rehm, Robin Room
[link url="http://www.camh.ca/en/hospital/about_camh/newsroom/news_releases_media_advisories_and_backgrounders/current_year/Pages/Public-health-guidelines-aim-to-lower-health-risks-of-cannabis-use.aspx"]Centre for Addiction and Mental Health material[/link]
[link url="http://ajph.aphapublications.org/doi/10.2105/AJPH.2017.303818"]American Journal of Public Health abstract[/link]