Cannabis Made Clear
Cannabis for Medical Uses
The legal use of cannabis for medical purposes in Canada predates its legalization for recreational purposes. Here’s what the research says about the effectiveness of cannabis for medical purposes.
Last updated January 20, 2025 | Published on June 20, 2022
Looking at dried flower or an infused oil, you probably can’t tell whether it’s from the recreational or medical market. In fact, it might be the same product. But there are important differences in how it’s distributed and why. Here’s what you need to know about how to access cannabis for medical use, and what the research says about the effectiveness of cannabis for medical purposes.
Is medical cannabis legal?
While access to cannabis for recreational use has been legal in Canada since October 2018, access to cannabis for medical use has been legal for a lot longer. In 2001, Health Canada introduced its first federal medicinal cannabis program, and by 2003, patients with an authorization from a healthcare practitioner have been able to legally purchase, possess and grow cannabis for medical purposes.
What’s the difference between recreational and medical cannabis?
Today, many of the same cannabis products are available in both the recreational and medical markets. What makes medical cannabis different is why it’s used and how it’s accessed.
Medical cannabis can be prescribed for a wide variety of therapeutic purposes only by healthcare practitioners, which include doctors and, in all provinces and territories other than Alberta, nurse practitioners. These healthcare practitioners oversee their patients, adjusting dosages, helping to avoid unwanted effects and steering clear of potential adverse interactions with other medications.
Using cannabis for any medical purpose should be done in consultation with and with authorization from a designated healthcare practitioner. A patient must provide a medical document to access medical cannabis, which is sold through different channels than recreational cannabis.
How is medical cannabis consumed?
Just like recreational cannabis, medical cannabis can be consumed in various ways and comes in a variety of formats. Here are the most common products used for medical purposes:
- dried flower, which can be either smoked or vaporized
- edibles, such as gummies, hard candies, chocolates and baked goods
- beverages, such as sodas, juices, tea and coffee
- capsules
- tinctures
- topicals, including creams, balms and patches applied directly to the skin
- oils and sprays
- suppositories
What the research says about cannabis for medical purposes
Clinical research on the effectiveness of cannabis for medical purposes is in the very early stages. While there are many pre-clinical studies underway, the body of conclusive evidence to support treating health conditions with cannabis is still small.
It’s important to note that much of the early research — including the findings summarized below — focused on pharmaceutical preparations of cannabis. However, more studies are now focusing on dried cannabis and related products that reflect those consumed for medical purposes.
What is medical cannabis used for?
According to The Health Effects of Cannabis and Cannabinoids — a review of scientific evidence related to the health effects and potential therapeutic benefits of all cannabis products (including prescription cannabinoid products dispensed by a pharmacist) by the National Academies of Sciences, Engineering, and Medicine — there is evidence demonstrating that cannabis and cannabinoids may be beneficial in managing the following symptoms.
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Chronic pain in adults: According to the results of randomized controlled trials of patients with chronic pain related to neuropathy, cancer, multiple sclerosis and musculoskeletal conditions, cannabis products may relieve symptoms for some people.
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Nausea: For patients experiencing chemotherapy-induced nausea and vomiting, cannabis products have been shown to reduce symptoms to similar effect as some conventional antiemetics used by cancer patients.
- Spasticity: Oral administration of cannabinoids has been found helpful in improving patient-reported pain from multiple sclerosis–related spasticity, an involuntary activation of muscles. (There is limited evidence to suggest improvements in clinician-measured symptoms.)
There is moderate evidence for the effectiveness of cannabis as a therapeutic treatment for:
- Sleep disorders: Researchers have found that sleep disturbances related to multiple conditions — namely obstructive sleep-apnea syndrome, fibromyalgia, chronic pain and multiple sclerosis — are lessened with cannabinoid treatments. Data suggests, however, that while low doses of THC appear to improve sleep, high doses of THC may cause or worsen sleep disturbances.
There is limited evidence for the effectiveness of cannabis as a therapeutic treatment for:
- Symptoms of Tourette’s syndrome
- Loss of appetite and weight loss associated with HIV and AIDS
- Symptoms of anxiety in people with social anxiety disorders (the effects of CBD show particular promise)
- Symptoms of post-traumatic stress disorder
Risks of medical cannabis use
While cannabis is often used medically, there are potential short- and long-term effects to consider for any cannabis use, depending on the method of consumption, dosage and individual factors. Here are the most common effects.
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Cognitive: Cannabis use can cause changes in perception and sleepiness, impair reaction time, memory and concentration, and cause anxiety and paranoia. Regular daily consumption, especially of high-THC products, may lead to cannabis use disorder or psychosis.
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Physical: Cannabis may cause dizziness, increased heart rate and, when inhaled through smoking or vaping, lung issues.
- Drug interactions: Cannabis may interfere with blood thinners, sedatives, blood pressure medications and other prescription drugs, potentially causing harmful effects.
For more information about using cannabis for medical purposes, please refer to the Government of Canada’s consumer information about medical cannabis.
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