Medical and Recreational Cannabis
Cannabis & Parkinson’s
There is currently no conclusive evidence demonstrating that cannabis is beneficial for people with Parkinson’s disease (PD). A limited number of studies examining certain cannabinoids for Parkinson’s symptoms have yielded mixed results (Health Canada, 2018a). If you are considering the use of cannabis for symptom management, consult with your doctor first. More research needs to be done to better understand the effects of cannabis for people with Parkinson’s.
The use of cannabis (also known as marijuana) has been legal for medical in Canada use since 2001. As of October 17, 2018, it was legalized for recreational use as well. In British Columbia, the legal age to purchase cannabis is 19. Recreational cannabis can be purchased in government-operated stores, both in-person or online. Cannabis smoking and vaping (act of inhaling and exhaling vapor) is prohibited wherever tobacco smoking is prohibited, as well as places where children commonly gather, such as playgrounds (Government of BC, 2018). More information on BC cannabis regulations can be found under Additional Resources at the end of this webpage.
Chemical Substances in Cannabis
The chemical substances in cannabis are called cannabinoids. These have an effect on cell receptors in the brain and body, and can change how those cells behave and communicate with each other. The two most commonly known cannabinoids are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD).
THC
THC is the most researched cannabinoid, and is responsible for the way your brain and body respond to cannabis, including intoxication, or the “high”. THC has some therapeutic effects, but may be harmful in higher concentrations. The potency (concentration or strength) of THC in cannabis is often shown as a percentage of THC by weight (or by volume of oil). Cannabis that contains very low amounts of THC in its flowers and leaves (less than 0.3%) is classified as hemp.
CBD
Unlike THC, CBD does not produce a high or intoxication. Some evidence suggests that CBD may block or lower some of the side of effects that THC has on the mind. This may occur when the amount of CBD is the same or higher than the amount of THC in the cannabis product. CBD is also being studied for its possible therapeutic uses (Health Canada, 2018b).
Potential Therapeutic Uses of Cannabis
Although Health Canada has produced information on its potential therapeutic effects, cannabis is not an approved therapeutic product. The educational material produced by Health Canada should not be interpreted as an endorsement of the use of cannabis for therapeutic purposes or of marijuana generally.
Your healthcare practitioner may authorize the use of cannabis for relief of symptoms associated with a variety of disorders, which may not have responded to conventional medical treatments. Both the potential therapeutic and adverse effects associated with cannabis use may vary depending on:
- the amount of cannabis used and the concentration of cannabinoids in the product,
- the frequency of cannabis use,
- the patient’s age and medical condition(s),
- previous experience with cannabis or cannabinoids, and
- the use of other prescription or non-prescription drugs.
THC acts on very specific targets, known as cannabinoid receptors, which are found throughout the body in most tissues and organs, but are specifically numerous in the brain and nervous system. Other cannabinoids, such as a CBD, may have targets other than cannabinoid receptors. Cannabinoid receptors are involved in the regulation of bodily functions such as heart rate, blood pressure, perception of pain, wake/sleep cycle, digestion, and many other functions (Health Canada, 2016a).
With respect to Parkinson’s disease, early studies have shown cannabis has the potential to allieviate symptoms such as tremor, pain, insomnia, and anxiety. Additionally, although it does not provide a cure or reverse the nerve damage caused by PD, there is evidence suggesting that it may support nerve growth and have neuroprotective effects (de Barros Viana et al., 2022). However, more research is needed to determine its true therapeutic potential for PD.
When should cannabis not be used?
According to Health Canada, cannabis should not be used if you:
- are under the age of 25
- have serious liver, kidney, heart, or lung disease
- have a personal or family history of serious mental disorders such as schizophrenia, psychosis, depression, or bipolar disorder
- are pregnant, are planning to get pregnant, or are breastfeeding
- are a man who wishes to start a family
- have a history of alcohol or drug abuse or substance dependence
Talk to your healthcare practitioner if any of the above conditions apply to you, in addition to your Parkinson’s disease. There may be other conditions where this product should not be used, but which are unknown due to limited scientific information.
Cannabis may also interact with several drugs. As such, be sure to tell your healthcare practitioner which prescription, non-prescription, or herbal products you are currently taking, particularly:
- any drugs which slow down the central nervous system, causing drowsiness. These may include sleeping pills, tranquilizers, some pain medications, some allergy or cold medications, or anti-seizure medications.
- antiretroviral drugs used in the treatment of HIV/AIDS, certain anti-depressants, stomach acid inhibitors, certain antibiotic and antifungal medications, certain heart medications, and Saint John’s Wort.
My doctor is not comfortable prescribing medical cannabis. What can I do?
Many doctors are unfamiliar with the research on medical cannabis, and as a result, are hesitant to prescribe it. In these situations, if you would like to try medical cannabis you may need to be your own advocate with your doctor. Bring documentation that explains the research and science behind cannabis and its therapeutic effects, as well as your experience if you have tried it recreationally. Some doctors may have negative attitudes towards the use of medical cannabis, but if you are able to explain how medical cannabis may be beneficial as a treatment option, you are more likely to receive their support (Medical Marijuana.ca, 2016).
If your doctor is not able to provide you with a prescription for medical cannabis, you may choose to visit a doctor who is a medical cannabis specialist. Greenleaf Medical Clinic is an option for getting connected to medical cannabis specialists. A referral from your GP may be required.More information and relevant forms are available on their website at www.greenleafmc.ca/patients
Dosing Methods
There is no scientifically defined dose of cannabis for any specific medical condition. If you have not consumed cannabis before, it would be prudent to have someone with you the first time you use it. Dosing remains highly individualized. The current information suggests most individuals use less than 3 grams daily of dried marijuana, whether that amount is taken orally, inhaled, or a combination of both (Health Canada, 2016). Doses of THC as low as 2.5-3 mg, and even lower, are associated with therapeutic benefits with minimal psychoactivity.
Inhaling
When smoking or vaporizing cannabis, effects may be felt within a few minutes and will generally peak within 30 minutes. Acute effects typically last between two to four hours, but may be longer (e.g., 24 hours).
Ingesting
When ingesting oils, foods, or capsules, acute effects may be felt as quickly as 30 minutes or as long as three to four hours after administration. This variability depends on factors such as the amount of food in the stomach. It is prudent to wait a minimum of two hours between administrations of single doses of oral products to prevent possible overdosing. Acute effects generally peak between three to four hours after dosing and can last eight hours or longer.
Topical Application
With topical application (e.g., oils and/or creams), it is not known how long it takes for potential therapeutic effects to appear, nor how long they last. There have been reports of hypersensitivity reactions, such as rashes or itching, when skin has come into contact with cannabis.
Health Canada advises patients with no prior experience with cannabis or cannabinoids to begin at a very low dose and to stop therapy if unacceptable or undesirable effects occur (Health Canada, 2016b).
Accessing Medical Cannabis Legally
Although both recreational and medical cannabis is legal in Canada, Health Canada continues to operate the medical cannabis system. To access medicinal cannabis (Health Canada, 2017):
1. Meet with your healthcare practitioner to discuss the use of cannabis for medicinal purposes.
2. Register with a licensed producer to obtain cannabis products for medical use, including fresh or dried marijuana, and cannabis oil. To register with a licensed producer of your choice, you will need to complete a registration form specific to that licensed producer and provide your original Medical Document Authorizing the use of Cannabis for Medical Purposes.
3. If approved for medical cannabis access, you are allowed to possess up to a 30-day supply of dried marijuana, or its equivalent. Your maximum amount is based on the lower amount of what your healthcare practitioner has recommended, or 150 grams.
4. You may switch to a different licensed producer at any time. Licensed producers are, however, not allowed to return your medical document. In order to switch licensed producers, you must:
- obtain a new medical document from your healthcare practitioner
- cancel your registration with your current licensed producer
- complete a registration form specific to the new licensed producer. Registration forms are available on the licensed producer’s website or by contacting them directly
- provide the original of your new medical document to the new licensed producer
Travelling with Cannabis
While cannabis is legal nationwide in Canada, cannabis cannot be transported across the border – into or out of Canada – even if you are authorized to use cannabis for medical purposes and even if you are travelling from an area where cannabis has been legalized or decriminalized. If you try to travel to other countries with cannabis in your possession, you may be subject to criminal charges. If you are travelling within Canada, it is your responsibility to learn the laws of the province or territory to which you are travelling (Government of Canada, 2018b).
Research on Medical Cannabis
Research is currently being conducted on medical cannabis. The Canadian Institutes of Health Research (CIHR) has made significant investments in research observing both the potential therapeutic effects, as well as potential adverse effects, of cannabis.
In November 2020, CIHR and its health partners invest more than $21 million in cannabis research. $19.3 million will be allocated to support researchers investigating the potential therapeutic effects and risks of cannabis use in various fields, including cancer, pain management, neurodevelopment, and the health of Indigenous Peoples. The Canadian Centre on Substance Use and Addiction is providing an extra $2.45 million to assess the public health and safety effects of various provincial or territorial policies concerning cannabis. These investments in cannabis research will strengthen the evidence base and expand cannabis research in areas where it is needed most (Canadian Institutes in Health Research, 2018).
Additional Resources
Cannabis Rules and Regulations | Government of BC | bit.ly/2QjdhWA
Learn about Cannabis | BC Cannabis Stores | bit.ly/2Qfo6J9
Cannabis in Canada | Government of Canada | www.canada.ca/cannabis | cannabis@canada.ca
Sources
Canadian Institutes of Health Research. (2021, March 24). Research in cannabis use. Retrieved from: http://www.cihr-irsc.gc.ca/e/50932.html
de Barros Viana, M., de Aquino, P. E. A., Estadella, D., Ribeiro, D. A., & de Barros Viana G.S. (2022). Cannabis sativa and cannabidiol: A therapeutic strategy for the treatment of neurodegenerative diseases? Med Cannabis Cannabinoids, 5(1), 207–219. https://doi.org/10.1159/000527335
Government of Canada. (2018, October 17). Cannabis and the border. Retrieved from: https://www.canada.ca/en/services/health/campaigns/cannabis/border.html
Government of BC. (2018, October 19). Cannabis. Retrieved from: https://www2.gov.bc.ca/gov/content/safety/public-safety/cannabis
Health Canada, Government of Canada. (2016a, August 19). Consumer information – cannabis. Retrieved from: www.canada.ca/en/health-canada/services/drugs-medication/cannabis/licensed-producers/consumer-information-cannabis.html
Health Canada, Government of Canada. (2016b, July). Access to cannabis for medical purposes regulations – daily amount fact sheet (dosage). Retrieved from: www.canada.ca/en/health-canada/services/drugs-medication/cannabis/information-medical-practitioners/cannabis-medical-purposes-regulations-daily-amount-fact-sheet-dosage.html
Health Canada, Government of Canada. (2017, January 5). Accessing cannabis for medical purposes from a licensed producer. Retrieved from: www.canada.ca/en/health-canada/services/getting-cannabis-from-licensed-producer/accessing-from-licensed-producer.html
Health Canada, Government of Canada. (2018a). Information for healthcare professionals: Cannabis (marihuana, marijuana) and the cannabinoids. Retrieved from: www.canada.ca/en/health-canada/services/drugs-medication/cannabis/information-medical-practitioners/information-health-care-professionals-cannabis-cannabinoids.html#a4.9.1.3
Health Canada, Government of Canada. (2018b, October 16). About cannabis. Retrieved from: www.canada.ca/en/health-canada/services/drugs-medication/cannabis/about.html
Medical Marijuana.ca. (2018, November 4). Speaking with your doctor. Retrieved from: www.medicalmarijuana.ca/patients/speaking-with-your-doctor/
Last updated: July 24, 2023