Cannabis: What Educators Need to Know

How can educators approach the topic of cannabis with students?

The legalization of recreational cannabis for adults who are 19 or older gives educators an opportunity to promote critical thinking around substance use. It also encourages students to engage in personal decision-making, now and in the future, that will help them to achieve their short-and long-term goals. While it is illegal for Ontario youth under the age of 19 to use, buy, possess, cultivate or share recreational cannabis, legalization for adults may prompt students to think more about this issue and come forward with questions.

To have a meaningful conversation with students, approach the topic of cannabis in a knowledgeable, supportive and non-judgmental way, and in the context of a positive educator-student relationship.

Take time to reflect back to when you were younger and what information you needed at that point in your life.1 Tailor the conversation to the students’ knowledge needs and provide appropriate information by considering:

  • the reasons why students use cannabis;
  • risks of cannabis use;
  • the student’s age and level of development;
  • the school/community/family context.

Like other substances, most students will not use cannabis, some will use it recreationally without developing problems, and a subset may develop problems as a result of their use. In your conversation, recognize the differences between the use of cannabis for recreational and for medical purposes, which requires a prescription under federal law.

Be aware of common myths that can influence students, such as the belief that trying cannabis is not harmful. The references and links provided at the end of this Info-Sheet offer more detailed information to assist with knowledge-building in this area. Health promotion, prevention and harm reduction approaches can be considered when talking with students about cannabis or other drugs. Health promotion and prevention approaches aim to promote well-being, reduce the number of students who will start using cannabis, delay initiation, and reduce the frequency of use. Harm reduction approaches aim to decrease the harms and risks associated with cannabis use. Harm reduction strategies have become increasingly accepted as a pragmatic and effective approach for individuals who may be at greater risk of using cannabis or are already using drugs. Providing evidence based information about harms and risks associated with cannabis can help potential users to make informed decisions about trying this drug, and about precautions they can take to minimize risks. Your local public health unit is a resource for information about health promotion, prevention and harm reduction approaches.

What is cannabis?

Cannabis (also called marijuana, weed, dope and pot) is a drug that comes from the cannabis plant. It consists of dried flowers and leaves that are greenish or brownish in colour. It can also be used for medical purposes, which requires a prescription under federal law. Different ways to use cannabis include, but are not limited to:

  • Smoked as a cigarette, often called a joint, spliff, or a blunt.
  • Smoked or vaporized (sometimes called vaping) through a pipe, bong, or e-cigarette.
  • Mixed in a drink or with food (such as tea, brownies, and candies), called edibles.
  • Consumed as a tincture (an alcohol-based extract) on its own or added to food or drinks.
  • Heated and inhaled (called dabbing) as oil, wax, or in a form called shatter that is made from cannabis resin also known as hashish.

Because cannabis is a psychoactive substance there are risks associated with using, regardless of how it is consumed. Some ways of using cannabis are more harmful than others (e.g., smoking can lead to lung damage). While vaping or consuming edibles may reduce some of the health risks, it is important to convey to students that they are not completely risk-free (e.g., edibles can lead to consumption of high doses, which can lead to acute impairment or adverse events). Some ways of using cannabis are more harmful than others (e.g., smoking can lead to lung damage). While vaping or consuming edibles may reduce some of the health risks, it is important to convey to students that they are not completely risk-free (e.g., edibles can lead to consumption of high doses, which can lead to acute impairment or adverse events).

In 2017, one in five (19%) grade 7-12 students in Ontario said they used cannabis at least once in the previous year. 2 In this group, most students reported that they used a bong, joint, or edibles. Use increases with grade and was highest in grade 12 (37%). Only 2% of students in grade 7 and 8 reported using cannabis. It’s important to remember that 81% of students in grades 7 to 12 reported that they have not used cannabis at all in the past year.

What is the impact of cannabis on emotions, cognition, and perception?

Cannabis contains THC (tetrahydrocannabinol), a chemical that causes a range of mental and physical effects (also known as a “high”). Cannabis can make some people feel relaxed and happy, but it can also cause confusion, drowsiness, forgetfulness, panic, delusions, and distorted perceptions. Studies show that the average potency of THC in cannabis today is almost 10% higher than it was 30 years ago. When cannabis is smoked or vaporized, the effects begin right away and can last six hours or longer. The effects of edibles may begin between 30 minutes and two hours after ingestion, and can last 12 hours or longer. Although edibles do not harm the lungs and respiratory system like smoking cannabis, it can take longer for their effects to be noticed. This delayed effect can cause a person to consume larger amounts than they intended in a short amount of time. Consuming large amounts of cannabis is not life threatening, unlike other substances, such as alcohol, opioids, and/or other drugs that can lead to fatal overdoses. However, consumption of large amounts of cannabis can have negative consequences, such as increased risk of paranoia, delusion, or psychotic episodes.

Key Cannabis Facts

  • The law in Ontario for recreational cannabis: It is illegal for youth under the age of 19 to use, buy, possess, cultivate or share recreational cannabis. Smoking and vaping cannabis is prohibited in places where smoking tobacco or using e-cigarettes is prohibited. It cannot be smoked or vaped at school, on school grounds, on children’s playgrounds, and all public areas within 20 metres of these grounds, or consumed in any way in motor vehicles, motorized snow vehicles, and boats, subject to certain exemptions.
  • Recreational cannabis was not legalized because it is harmless. The federal government legalized recreational cannabis to create strict rules for producing, distributing, selling and possessing cannabis across Canada. The legalization aims to keep cannabis out of the hands of youth and protect public health and safety by allowing adults to access cannabis legally.
  • Most students do not use cannabis. The majority also report that they do not plan to use cannabis now that it is legal for adults.
  • Cannabis is a psychoactive drug, so it can affect memory, concentration, mental health, and physical well-being. Cannabis use can harm young people’s health and the development of their brain. This is important for youth, since the human brain is not fully developed until the age of 25. Cannabis smoke contains levels of chemicals that are similar to tobacco smoke, which can increase the risk of cancer and lung disease.
  • Cannabis can be addictive. About one in six teens (aged 12-17 years old) who start using cannabis will develop an addiction. Those addicted can experience withdrawal symptoms when they stop, which can include difficulty sleeping, depressed mood, and increased anxiety.

What are the risks for youth of using cannabis?

Trying cannabis is unlikely to cause serious problems in most people, but even occasional use can be harmful. Youth who use cannabis at a young age, often, and over the long-term (for months or years), are at risk of long-term health and social problems. For example:

  • Harm to the brain, such as problems with memory, concentration, thinking, learning, handling emotions, and decision-making. 7, 8 Research shows that cannabis use can affect normal brain functioning in youth and young adults up to age 25, and may alter brain development.
  • Problems with academic progress, such as impact on learning and attention, difficulty with completing school work, lower school performance, and increased risk of dropping out of high school.
  • Mental health problems, such as psychosis or schizophrenia and, possibly, depression, anxiety, and suicide, especially if there’s a personal or family history of mental illness.
  • Difficulties with relationships, such as conflicts at home, school, or work.
  • Physical health harms, such as lung and respiratory problems from smoking cannabis.
  • Addiction, such as difficulty controlling how much or how often the person uses it, even when it’s causing them challenges in their life. Cannabis can be especially addictive for youth.

What are the signs that a student may have a problem with cannabis or other substances?

Like other substances, most youth will not use cannabis, some will use it recreationally without long term problems, and a subset may develop problems due to sustained use over time.2 In 2017, 1.9% of students in grade 9 to 12 reported symptoms of cannabis dependence.2 It is sometimes hard to detect a problem with cannabis use. Talk to your students and find out if there is a problem. Some signs of a cannabis problem can look like typical youth behaviour. For example:

  • Ignoring responsibilities at work, school, or home.
  • Giving up activities that they used to find important or enjoyable.
  • Using more cannabis, more frequently.
  • Feeling unable to cut down or control cannabis use.
  • Changes in mood (e.g., feeling irritable and paranoid).
  • Changing friends.
  • Having difficulties with family members, friends, and peers.
  • Being secretive or dishonest.
  • Changing sleep habits, appetite, or other behaviors.
  • Borrowing money or having more money than usual.

How can I promote student wellbeing and prevent harms related to cannabis?

Consider the following suggestions when speaking with students about cannabis as well as other substances, like alcohol:

  • Encourage students to avoid or delay using cannabis. Reinforce to students that the best way to prevent harm when it comes to cannabis is to not use it at all. Remind students that it is illegal for youth under the age of 19 to use, buy, possess, cultivate, or share recreational cannabis, and that it carries health, mental health, and cognitive risks, particularly for people under age 25.
  • Provide students with opportunities to learn about cannabis legalization. The topic can be explored through assignments, classroom debates, discussion of current events, and/or school-wide projects.
  • Suggest that students talk to a trusted adult. There are many people who can help a student to understand the facts about cannabis, how to reduce harms, and how to respond to peer pressure (e.g., a parent/guardian, family member, teacher, school staff member, faith/cultural leader, physician, or nurse). Students can be reminded that they have many adult allies who can support their decision-making.
  • Encourage students to build positive friendships as well as community and school connections. Healthy relationships with parents and peers can help protect students from substance use problems. 20 Seek out ways to help students build positive relationships with peers, teachers, or within the community.
  • Help students explore ways to manage stress and feelings without cannabis. Some young people use cannabis to help them deal with boredom, stress, sadness, or depression.
  • Help students find other ways to feel good or to help them manage feelings, like talking to a person they trust, seeking mental health and addiction supports, and engaging in clubs, sports, hobbies, or other activities.
  • Remind students that they have a choice if others pressure them to use cannabis. Feeling social pressure from friends or others to use cannabis can be challenging, but it is important for students to know that most students do not use cannabis.
  • Remind students to never ride with a driver who is under the influence of cannabis or any other substance. Driving after using cannabis doubles the chances of having a motor vehicle collision.

How can I talk to older students?

In addition to the messages above, consider the following suggestions for older students or those who are at higher risk of using cannabis:

  • Remind students that driving under the influence of cannabis is dangerous and illegal. It is critical to emphasize to students that to stay safe, they should never drive under the influence of cannabis. Impairment from cannabis can last at least six hours, but could be longer, more than 24 hours, depending on the person and the product used. Using cannabis and alcohol together further increases impairment. In Ontario, there is zero tolerance for young and new drivers; that is, they are not allowed to have any cannabis in their system if driving a motor vehicle.
  • Encourage students to avoid mixing or using cannabis with alcohol, tobacco, or other substances. Mixing drugs can make their effects unpredictable, increase the level of impairment, and cause negative side effects.
  • Encourage students to limit the amount of cannabis they use at one time and reduce how often they use it. Frequent cannabis use is linked to higher risk of physical health and mental health problems, and can have a negative impact on relationships.
  • Guide students and their families to specialized support if their cannabis usage is frequent and/or problematic. There are addiction specialists in many communities who can help, such as mental health and addiction nurses who are focused on working with students with mental health or addiction issues.

Where educators and parents can find more help and information

Information on the legalization of recreational cannabis in Ontario:

Educator resources:

Ministry of Education’s web page:

Information and guidance related to substance misuse:

Cannabis Education Resources:

Parent resources:

Ministry of Education’s web page:

School Mental Health ASSIST web page:

Fact and fiction about cannabis:

Cannabis talk kit, know how to talk with your teen:

Resources on how to talk to youth about drugs:

Talking pot with youth, a cannabis communication guide for youth allies:

Talking with teenagers about drugs:

Talking with youth:

Canada’s Lower-Risk Cannabis Use Guidelines:

Youth resource:

Evidence-based recommendations for lowering the risks of cannabis use: /media/files/pdfs—reports-and-books—research/canadas-lower-risk-guidelines-cannabispdf.pdf

Data on substance use among students in Ontario:



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