How cannabis use affects health including mental health concerns, risks for pregnancy and breastfeeding and combining cannabis with other substances and medications.
Cannabis is a product of the cannabis plant. It contains over 100 chemicals called cannabinoids that affect the brain and body. The two best-known cannabinoids are:
Cannabis comes in many forms, including dried cannabis, cannabis extracts, cannabis topicals and edible cannabis (cannabis-infused food and drinks).
Cannabis can be used to make a wide range of products that are different in: appearance and consistency, taste and smell, amount of THC (tetrahydrocannabinol), amount of CBD (cannabidiol) and how they are used (i.e., inhaled, ingested).
There are short-term and long-term health effects and risks associated with cannabis use, particularly for persons under the age of 25, during pregnancy and while breastfeeding, and for persons living with or with a family history of mental illness.
Everyone's response to cannabis is different. It depends on age, pre-existing medical conditions, how much is used, how often and how long cannabis has been used before. A person’s response also depends on where it is being used, whether food, alcohol, other drugs, or health products have been consumed, the amount of THC (tetrahydrocannabinol) and CBD (cannabidiol) in the product, and how it has been consumed.
If you smoke, vape or inhale cannabis, the effects can be felt almost immediately. If you consume cannabis as a food or a drink, the effects may be more delayed and can last longer.
A person’s response to cannabis can also be different from one time to the next.
The physical effects of cannabis may include:
Cannabis use can affect everyone’s health differently. A person’s level of risk depends on the factors, such as:
These health effects and risks are possible for anyone who uses cannabis:
There is no known safe amount of cannabis use during pregnancy or breastfeeding. The effects of cannabis can be passed on to a baby during pregnancy or while breastfeeding. Some of these effects can last the child’s lifetime.
The compounds and toxins in cannabis are passed through the blood to the unborn baby and through breast milk.
Cannabis in all forms, and no matter how it is used, can affect a baby’s growth and brain development. Cannabis use during pregnancy can lead to babies being born too small and too early. As a baby grows, their brain goes through many changes that can be altered by cannabis. It can also interfere with their attention, memory, and reasoning abilities, behaviour and processing of emotions, and problem-solving skills.
Being exposed to cannabis during pregnancy and breastfeeding can increase a child’s risk of:
Not using cannabis or CBD (cannabidiol) during pregnancy or when breastfeeding is the safest option for you and the baby. If you are, or are thinking about, using cannabis during pregnancy to manage nausea, anxiety, or pain, consider speaking with a health care provider to discuss your situation and to explore your options. There are other safe and effective options that can help.
Society of Obstetricians and Gynaecologists of Canada
Canadian Centre on Substance Use and Addiction (PDF)
Using cannabis with other substances, including alcohol, opioids, cocaine, prescribed or over-the-counter medications, can lead to negative health effects, increased risk of harm and be dangerous.
Be aware of what happen when mixing cannabis with other substances.
Consuming cannabis with alcohol increases the level of impairment, risk of over-intoxication and the risk of injury or death.
Smoking cannabis with tobacco increases exposure to chemicals that can increase the risk of developing lung and heart disease. Using cannabis with tobacco can increase the risk for dependence on these substances more than smoking either one alone.
Combining cannabis with other substances such as cocaine, opioids, heroin, etc. can increase a drug’s effects, and lead to interactions that can be dangerous.
Cannabis can interact with medications and have a negative effect on health.
Medications that can interact with cannabis include:
Canadian Centre on Substance Use and Addiction (PDF)
Canadian Centre on Substance Use and Addiction (PDF)