Information about cannabis for recreational use

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Learn about cannabis and find out about the short- and long-term effects of using it recreationally.

Key points

  • Cannabis refers to a group of plants that contain chemical substances, including cannabinoids such as THC and CBD.
  • Cannabis can be consumed by smoking or vaping, eating cannabis products such as baked goods and candies, or applying it to the skin in the form of lotions or ointments.
  • You must be 19 and older to legally buy, use, possess and grow recreational cannabis in Ontario.
  • Short-term effects of cannabis use can include feeling relaxed, being sociable, increased heart rate, difficulty concentrating, delayed reaction time, feeling anxious or panicky, and distorted thoughts and/or paranoia.
  • Long-term effects of cannabis use can include: long-term impaired working memory, emotional dysregulation, poor attention and impulse control; increased risk of changes in thoughts, feelings and behaviours; cannabis hyperemesis (severe and repeated bouts of vomiting); and cannabis dependence.

What is cannabis?

Cannabis (also known as marijuana, weed and pot) refers to a group of plants that are grown around the world, including Canada. The cannabis plant contains many chemical substances, including over 100 "cannabinoids".

What is a cannabinoid?

Cannabinoids affect cells in the brain and the body. They can change how those cells behave and communicate with each other.

What are examples of cannabinoids?

  • THC (delta-9-tetrahydrocannabinol) is a cannabinoid you may hear about the most. It is a "psychoactive" component, meaning that it is responsible for the way your brain and body respond to cannabis, including the "high" or intoxicating effect.
  • CBD (cannabidiol) is also a cannabinoid. While it is also psychoactive, it does not produce a high or intoxication and is often used for medicinal purposes.

Each cannabinoid works on different cannabinoid receptors located in the brain or other parts of the body. Different formulations of cannabis contain varying amounts of THC and CBD, so the effects of cannabis on your body will depend on this, as well as how the cannabis is used (e.g., smoked, ingested, applied to the skin).

How is cannabis consumed?

Cannabis can be consumed through smoking or vaping the flower of the plant, or plant-based products. The active compounds can be extracted into edible forms (baked goods, candies, oils and beverages) and eaten. They are available both commercially and homemade. Cannabinoids can also be absorbed through the skin from topical cannabis products in the form of lotions or ointments.

What is cannabis used for?


People often use cannabis to experience feelings of relaxation and contentment. You must be 19 and older to legally buy, use, possess and grow recreational cannabis in Ontario.

Although recreational cannabis use under the age of 19 is illegal in Canada, cannabis is one of the most frequently used substances by teens. Most teens who have tried cannabis first used it at 14 years of age; and one in five cannabis users (aged 16-19 years) report daily use. Daily use can result in cannabis dependence and greatly increases the risk of longer-term effects on the brain and other areas of health and well-being.


Cannabis has been used for a variety of purposes including appetite stimulation in serious illness, pain relief and anti-seizure therapy for people with rare forms of epilepsy. There are no age restrictions for the use of medical cannabis in Canada.

What is known about the effects of recreational cannabis in teens?

Short-term effects and risks

In the short-term, cannabis can cause you to:

  • feel more relaxed
  • be more sociable
  • have an increased heart rate
  • have difficulty concentrating, which can impact your learning, problem-solving, and school performance
  • have a delayed reaction time in response to changes in your environment (e.g., when you are driving)
  • feel anxious or panicky
  • experience distorted thoughts and perceptions and/or paranoia

Depending on your age, weight and how you consume it, cannabis can also affect your balance.

Longer-term effects and risks

Regular and frequent cannabis use is associated with the risk of a number of long-term effects on your physical and mental health.

The long-term brain and mental health effects of cannabis use can impact teens in particular because the frontal lobes of their brains are still developing well into their twenties. This region of the brain is responsible for your working memory, emotional regulation, attention and impulse control, and is especially vulnerable to the effects of cannabis (and other drugs, including alcohol).

Regular substance use, including cannabis use, in teens is linked with an increased risk of changes in thoughts, feelings and behaviours. Cannabis use can worsen any existing depressive and anxiety disorders you may have and has been associated with the development of schizophrenia and psychosis. This risk is higher in people with a family history of the disorder.

Teens (and adults) who use cannabis regularly can also develop cannabis hyperemesis, a syndrome where you have persistent nausea and vomiting that is only relieved by reducing/stopping your cannabis use. Taking hot showers can relieve the symptoms but will not prevent vomiting from recurring.

In addition, one in six teens who use cannabis frequently will develop cannabis dependence. Cannabis dependence includes needing to use more cannabis over time to have the same effect, and/or having difficulty sleeping, and being irritable when using less or stopping the use of cannabis.

Using cannabis while driving

Driving while high on cannabis is against the law in Canada. Cannabis can impair your driving by slowing your reaction time and affecting your ability to concentrate. Because it comes in different potencies and affects each person differently, it is not known how long you should wait to drive after consuming cannabis. It is important to recognize the dangers of driving under the influence of any substance and consider your options for getting home safely.

Last updated: May 25th 2022