Experts highlight the particular health risks of cannabis edibles, which were recently legalized in Canada.
Cannabis, produced from the leaves and flowers of cannabis plants, contains over 100 chemical compounds called “cannabinoids”. Two key active ingredients are tetrahydrocannabinol (THC) and cannabidiol (CBD). Cannabis has several effects on the brain and body. It produces an intoxicated “high” feeling, drowsiness, and impairment of concentration and memory thought to be mainly linked to the effects of THC. Cannabis also has anti-anxiety, analgesic, and anti-inflammatory effects thought to be mainly linked to the effects of CBD. People use cannabis as a recreational drug or to treat certain medical conditions, such as multiple sclerosis, chronic pain, or nausea related to cancer therapy, where there is some evidence of benefits.
Cannabis edibles recently legalized in Canada
Cannabis must be heated to activate the cannabinoids and no effects are produced by ingesting the raw unprocessed plant. Users consume cannabis by smoking or vaping, or by eating or drinking cannabis “edibles” – food, drinks, or oils that have been infused with cannabis and heated.
There is much debate around the regulation of cannabis use, both for medicinal and recreational purposes. The legal status of the drug varies in different countries. In Canada, controlled medicinal use of cannabis was legalized in July 2001 and recreational use in June 2018. Regulatory changes in October 2019 permit controlled production and sale of cannabis edibles. This form of cannabis poses particular health risks, which were recently highlighted by experts in the Canadian Medical Association Journal.
Cannabis edibles have particular health risks
Cannabis edibles are already popular in Canada. The National Cannabis Survey in 2019 found that 27% of respondents who had used cannabis in the past three months had consumed edible forms, presumably through home preparation or illegal channels. Edibles are usually viewed as a safer alternative to smoking or vaping cannabis, as there is no smoke inhalation into the lungs, but they are associated with other health risks.
An important concern is the delay in onset of effects with cannabis edibles compared to smoking. Someone smoking cannabis may feel effects within minutes of inhalation. However, with cannabis edibles, effects can take up to four hours to develop and may last for up to eight hours. This increases the risk of overdosing from overconsumption and lengthens the period of impairment. Individuals can have different responses to different edible products and this could also lead to overdosing. New users unfamiliar with cannabis edible products and their effects are at particular risk.
Children or pets may accidentally ingest cannabis edibles, some of which look like candies or other food and drink. After the legalization of cannabis edibles in Colorado, USA, there was a 70% increase in calls for accidental cannabis exposure in children between 2013 and 2017.
Elderly people and young adults may also have specific risks from cannabis edibles related to mental well-being. Some older adults use cannabis to manage chronic medical conditions. In this group, cannabis use has been linked to mental impairment, risk of falls, heart rhythm disruption, and interactions with their other medications. A recent Canadian survey in young adults found there is a common misperception in this group that cannabis edibles have a beneficial effect on mood, anxiety, and sleep. However, cannabis use in young adults can impair brain development and lead to mental health problems.
New regulations address some health risk concerns
The new regulations for cannabis edibles address some health concerns by outlining dosing limitations and requiring standardization of dosing information. The regulations also prohibit the combination of cannabis edibles with other psychoactive ingredients such as nicotine or alcohol. Edibles must be stored in plain, child-resistant packaging and display a standardized symbol and health warning. There are also restrictions on marketing claims and strict controls on manufacturing and production.
Health professional must inform the public about the health risks associated with cannabis edibles
“Physicians should routinely question patients who ask about cannabis about their use or intended use of edible cannabis products so that they can counsel these patients regarding child safety, potential for accidental overconsumption and delayed effects, and potential for interactions with other substances such as alcohol, benzodiazepines, sleeping aids, and opioids,” recommend experts Dr. Jasleen Grewal and Dr. Lawrence Loh from the University of Toronto, Canada, who authored the article. Physicians should advise strongly against driving after consuming cannabis edibles. They should also discourage the consumption of illicit or homemade cannabis edibles. These may cause overdose due to variable THC content or may be contaminated with harmful substances or other drugs. The authors also stress that population monitoring to evaluate the effects of legalized cannabis edibles is essential.
Written by Julie McShane, MA MB BS
- Grewal JK, Loh LC. Health considerations of the legalization of cannabis edibles. CMAJ January 6, 2020 192(1)E1-E2. Doi: https://doi.org/10.1503/cmaj.191217
- Canadian Medical Association Journal. Press release 6 Jan 2020. “Cannabis edibles present novel health risks” https://www.eurekalert.org/pub_releases/2020-01/cmaj-cep123019.php
- Canadian Public Health Association Resources and services. Cannabasics https://www.cpha.ca/cannabasics
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