Cannabis Information for Older Adults

Last revised: August 28, 2025

Cannabis is a plant that has hundreds of chemicals, many of these chemicals are called cannabinoids. The most common cannabinoids are THC (tetrahydrocannabinol) and CBD (cannabidiol).

• THC is psychoactive, it affects your brain and changes how you think, act and feel.
• THC is what causes a “high”. The higher the level of THC, the stronger the effects.
• THC is mostly responsible for the health risks associated with cannabis.
• CBD is non-psychoactive, meaning it does not cause intoxicating effects and can lessen the effects of THC. CBD is being studied for possible medical uses.

Cannabis affects everyone differently, an individual can have different experiences each time they use cannabis. Current cannabis products often have higher THC levels than in the past, this means the effects can be much stronger, even for people who have used cannabis before.

The aging process can affect how adults over 55 respond to cannabis

As we age, our body’s ability to process drugs and substances changes. Adults over 55 are more likely to experience harm from cannabis, especially if they have certain pre-existing health conditions, take medications or other health products. Due to the potential health risks, consider not using cannabis, if you are an older adult with the following conditions:

• Liver disease
• Kidney disease
• Heart or blood vessel disease, unstable blood pressure
• Cognitive impairments or problems with balance
• History of mental health challenges or substance use challenges or disorders

Using cannabis while taking prescription or non-prescription health products can increase the risks of side effects. If you are currently taking any prescription or over-the-counter medications, it is important to talk to your health care provider if you’re considering cannabis for medical or non-medical purposes. They can assess any interaction cannabis may have with your medications.

For more information, visit Health Canada’s webpages on medical use of cannabis and consumer information on cannabis.

Older adults with a heart condition are at greater risk for a heart attack or stroke

Cannabis can raise your heart rate and blood pressure. This may:

• Stress the heart and cause discomfort or anxiety
• Increase the risk of a cardiac event such as arrhythmia, angina, heart attack or stroke, for those with heart conditions

Cannabis may lower blood pressure, which can cause:

• Dizziness, light-headedness, fainting
• Increased risk of falls, especially when combined with alcohol or other substances

Cannabis and Liver Health

The liver processes cannabis and other substances and drugs. In older adults:

• Cannabis and medications may stay in the body longer, increasing side effects
• High daily CBD use (over 240mg) may affect liver health
• Daily cannabis use may worsen liver disease in people with chronic hepatitis C

Cannabis can affect how your brain works

THC is psychoactive, meaning it affects your brain and the way you think, act and feel. This can include feeling high, having trouble concentrating, slower reaction, and misperceptions. These effects can last between 6 to 12 hours depending on the amount of THC and the method of use. THC can affect the brain by causing:

• Anxiety, paranoia, confusion, hallucinations
• Drowsiness, disorganized thoughts
• Memory, attention, and coordination problems
• Increased risk of falls, injuries, or accidents

Cannabis and Mental Health

Cannabis can affect your mental health, especially with regular or high-THC use. Older adults can experience loneliness, isolation, depression or loss, using cannabis to cope can sometimes make these feelings worse.

Regular use can lead to a cannabis use disorder or dependence. If you are dependent, it can be hard to reduce your use or quit. Withdrawal symptoms may include:

• Irritability or anxiety
• Nausea or upset stomach
• Trouble sleeping
• Loss of appetite
• Sweating

Cannabis use can increase the risk of psychosis and schizophrenia if you have a family history of these conditions. Temporary psychosis is possible if you use too much THC at one time. Symptoms may include paranoia, delusions and hallucinations.

Lower risk cannabis use

If you are planning to use cannabis, read more information about using legally and follow these lower risk tips. Even a small amount of cannabis can affect a person’s ability to drive. Learn more about impaired driving and the penalties you could receive by visiting Impaired driving | ontario.ca.

For more information on resources and services, visit our Mental Health, Addictions and Substance Use Health Services and Resources webpage.