Read our full statement on cannabis and the treatment of dementia.
Recreational cannabis or marijuana is legal in Canada since October 17, 2018.
Before that date, the use of cannabis for medical purposes was only legal if you were authorized by a healthcare provider and you were registered with a licensed producer or with Health Canada.
Health Canada has since updated their site with information on accessing cannabis for medical purposes.
What is cannabis?
- Cannabis is a plant that is also referred to as marijuana. It contains a variety of chemical compounds called cannabinoids. The most well-known of these is tetrahydrocannabinol (THC), the compound primarily responsible for the psychoactive effects of the drug (the “high”). Scientists have identified over 70 different cannabinoids in cannabis, each with various effects on the body.
- Cannabinoids also exist naturally within the human body (known as endocannabinoids) or can be produced synthetically. One example of a synthetic cannabinoid is nabilone, a drug used to treat severe nausea and vomiting caused by chemotherapy.
How does cannabis affect the brain?
- The cannabinoids in cannabis interact with a network of cell receptors throughout the human body called the endocannabinoid system. This system exists in our bodies to interact with the naturally-occurring endocannabinoids, which play a role in regulating a variety of different bodily functions.
- Cannabinoid receptors are found in most tissues and organs, but are particularly numerous in the brain. When cannabis is consumed and its cannabinoids act on these receptors, they alter the release of neurochemicals in the brain, which changes how brain cells communicate with each other. This, in turn, affects various processes within our bodies, including appetite, pain, mood, memory and learning.
Research on cannabis and Alzheimer’s disease
- Researchers still have a lot to learn about the long-term effects of cannabis on the brain. Some studies have shown that long-term cannabis use is associated with memory problems.
- A few clinical trials have identified that cannabis can help manage behavioural symptoms in people with dementia, including agitation and aggression, but only in some cases.
- Other trials have studied the effects of cannabinoids (including THC and the synthetic nabilone) on behavioural symptoms, but more investigation is required.
- The Alzheimer Society Research Program has funded research on how endocannabinoids affect mood and anxiety in dementia and how the synthetic cannabinoid nabilone can treat agitation in Alzheimer’s disease.
While there is ongoing promising research on the effects of cannabis, there is currently no evidence that cannabis is useful for the treatment or prevention of Alzheimer’s disease.
In fact, some research indicates that long-term use of cannabis may be harmful and result in memory problems.
If you are living with Alzheimer’s disease or another form of dementia and have concerns or questions about cannabis, the Alzheimer Society recommends that you consult with your family doctor or other healthcare provider.
More useful links and resources
Cannabis and the treatment of dementia. Alzheimer Society of Canada, 2018. Our full position statement on this topic.
Cannabis and older Adults eLearning modules. Developed for physicians, nurse practitioners, other healthcare providers and healthcare students this elearning resource includes information on assessing appropriateness of medical cannabis for older adults, optimizing communication with older adults about cannabis and monitoring for potential adverse effects of cannabis among older adults. Created by the Canadian Coalition for Seniors’ Mental Health in partnership with Baycrest and funded by Health Canada (Substance Use and Addictions Program).
Clearing the air about cannabis and dementia. Alzheimer Society of Canada, 2018. This blog discusses research on the potential of cannabinoids to reduce agitation in people living with dementia. Authored by Dr. Krista Lanctôt, PhD, Professor in the Department of Psychiatry and the Department of Pharmacology and Toxicology at the University of Toronto and Senior Scientist with the Hurvitz Brain Sciences Research Program at Sunnybrook Health Sciences Centre.
Cannabis and dementia: Weeding through the evidence. brainXchange, 2019. This webinar outlines the rationale for use of cannabinoids to treat agitation in people living with dementia, and present results of the most recent trial of a cannabinoid for agitation. Presented by Dr. Krista Lanctôt, PhD, Professor in the Department of Psychiatry and the Department of Pharmacology and Toxicology at the University of Toronto and Senior Scientist with the Hurvitz Brain Sciences Research Program at Sunnybrook Health Sciences Centre.
Accessing cannabis for medical purposes. Health Canada. This government page details information on current and past regulations, how to get cannabis for medical purposes from a licensed producer and how to apply to produce cannabis for your own medical purposes.