Cannabis and Your Health
Cannabis (marijuana, pot, weed) comes from the plant, Cannabis sativa. Once grown, the leaves and flowers can be dried for use or made into oils, waxes, and other products for consumption. Cannabis can be smoked in a joint, pipe or bong, or vaporized. It can also be eaten, brewed as a tea or made into skin lotions.
Cannabis contains many chemical compounds. Two that receive a lot of attention are THC (delta-9-tetrahydrocannabinol) and CBD (cannabidiol). THC is what makes people "high"; CBD is used for its pain-killing properties and doesn't make you feel "high."
Non-medical cannabis was legalized in 2018. However, legal doesn't mean safe. There are risks associated with cannabis use, including short-term and long-term health effects.
You can download the following Government of ±¦ÍþÌåÓý resources:1. Short-term Effects
Cannabis affects everyone differently. After using cannabis, the user may experience effects like red eyes, sleepiness, problems with memory and increased hunger (also known as "the munchies"). They may also become paranoid and nervous. Cannabis can affect short-term memory and the ability to concentrate. It can also increase heart rate and decrease blood pressure.
Cannabis can also slow down reaction time and affects attention span. It's important that if you use cannabis, you do not drive – it is considered impaired driving and you could be charged. For more information, see the Cannabis and Driving section.
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2. Long-term Effects
If cannabis is smoked, it could cause problems with the immune system, lungs and airways.
Long-term effects may include:
- coughing;
- wheezing;
- shortness of breath after exercise;
- chest tightness; and
- severe and reoccurring bronchitis.
Frequent cannabis use (use at least once a week over a period of months or years) can affect memory, attention, learning and problem-solving. Heavy and regular use can also increase the risk of depression and anxiety.
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3. Effects on Youth and the Developing Brain
The teen years are a critical time for brain development. The brain is not fully developed until around age 25. Using cannabis can affect how the brain forms and grows, which means the brain needs to work harder to respond in a given situation.
Studies have shown that heavy cannabis use in adolescence can permanently alter brain chemistry, which could affect how youth learn, behave, respond and act.
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For Youth:
For Parents:
4. Effects on Women who are Pregnant and/or Breastfeeding
Using cannabis during pregnancy may affect the baby. No known amount of cannabis use is safe during pregnancy and when breastfeeding.
The toxins in cannabis are carried through the mother's blood to her fetus during pregnancy and in the breast milk following birth. Cannabis is fat soluble, which means that its chemicals are in breast milk and can be passed along to the baby during breastfeeding. Heavy cannabis use during pregnancy can also lead to lower birth weight of the baby.
Research suggests a link between a mother's use of cannabis during pregnancy and learning problems in children, as well as children having difficulty sitting still, paying attention and making good decisions.
There could be long-term effects on children and teens such as:
- hyperactive behaviour;
- decreases in:
- memory function;
- the ability to pay attention;
- reasoning; and
- problem-solving skills.
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5. Effects on Mental Health
Frequent cannabis use has been associated with an increased risk of suicide, depression and anxiety disorders.
For some people, using cannabis can increase the risk of developing more severe mental health issues. People could be at increased risk if they:
- start using cannabis at a young age;
- use cannabis frequently (daily or almost every day); or
- have a personal or family history of psychosis and/or schizophrenia.
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6. Addiction
Contrary to popular belief, people can become addicted to cannabis. Individuals who use cannabis can develop a cannabis use disorder. This can sometimes lead to physical dependence and addiction, especially with continued, frequent and heavy cannabis use.
Research has shown that THC in cannabis causes an increase in levels of dopamine (the pleasure chemical) in the brain. This motivates people to keep using it.
If people feel good when they use cannabis they will want to have that feeling again. For that reason, it is important for people to be able to create those positive feelings without the use of drugs.
Addiction can develop at any age but youth are especially vulnerable as their brains are still developing.
If you or someone you know is struggling with an addiction to cannabis, contact HealthLine 811 and ask for help. You should know that help is available and recovery is possible.
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7. Cannabis and Second-Hand Smoke
Any kind of smoke is harmful. In fact, studies have shown that cannabis smoke contains many of the same harmful substances as tobacco smoke. Like smoking cigarettes, smoking cannabis can damage your lungs and can cause bronchitis-like symptoms, coughing and wheezing which can, for example, affect athletic performance. While the effects of second-hand smoke from tobacco are well known, more research is needed to better understand the health effects of second-hand smoke from cannabis.
8. Risk of Use with Medications
Using cannabis or medical marijuana with other medications could be dangerous. When you visit your health care provider, tell them about your cannabis use as well as any drugs, medications (prescription and over-the-counter), supplements and herbal products you are using. This can include:
- any drugs which cause drowsiness (sleeping pills, tranquilizers, some pain medications, some allergy or cold medications, or anti-seizure medications); and
- antiretroviral drugs used in the treatment of HIV/AIDS, anti-depressants, stomach acid inhibitors, certain antibiotic and antifungal medications, certain heart medications, and Saint John's Wort.
For more information, speak to your pharmacist or health care provider, or visit .
9. Cannabis for Medical Purposes
Medical cannabis (marijuana) was made available in Canada in 2016. For more information, visit .
in ±¦ÍþÌåÓý has developed a with information for people thinking about starting medical cannabis
It is important to note that driving while under the influence of medical cannabis is considered impaired driving. This is unsafe for the driver, passengers and others. It could also lead to legal consequences, including being charged.