Know the facts. Use your instincts.

Some youth may think cannabis is harmless…
but the opposite is true.

It’s hard to predict how cannabis will make you feel. Everyone reacts to it differently. Even if cannabis makes you feel happy, relaxed, or less nervous in the short-term, the long-term effects may be different. Regular and heavy cannabis use before age 25, when the brain is fully developed, can result in:

  • negative impacts on mental health
  • decreased motivation
  • difficulty learning and poorer grades
  • addiction

Plus if you’re under 19 it’s still illegal.

Even if it seems like everyone around you is using, remember, the majority of youth DON’T use cannabis. Four out of five Ontario students report not having used cannabis in the last year.[1]

It is safer not to use cannabis but if you choose to use learn ways to reduce some of the risks to your brain and your body.

[1] Source: Boak, A. Hamilton, H.A., Adlaf, E.M., & Mann, R.E. (2017). Drug use among Ontario students, 1977-2017: Detailed findings from the Ontario Student Drug Use and Health Survey (OSDUHS) (CAMH Research Document Series No. 46). Toronto, ON: Centre for Addiction and Mental Health.

Using Cannabis?

Tips to Reduce Your Risk

It is safest to not use cannabis (marijuana, weed, pot) for non-medical reasons. But, if you choose to use here are some ways you can use more safely:

Keep Sharp

The brain continues to develop until your mid-20s. Regular and heavy cannabis use before the brain is fully developed can make it harder to do well at school or on the job. It may also be harder to stop using cannabis if you start at a young age.

Know What You're Using

Don’t use synthetic cannabis like “Spice” or “K2.” Synthetic cannabis is not cannabis: It is made by spraying unregulated chemicals onto any type of shredded plant. These chemicals can be toxic and may result in serious health problems.

Go Easy on Your Lungs

Like smoking cigarettes, smoke from cannabis can harm your lungs and make it harder to breathe. To reduce breathing problems consider a vaporizer or edible cannabis instead of smoking. If you do smoke cannabis, avoid deep inhalation and breath-holding as this increases the amount of toxins brought into the lungs.

Start Low. Go Slow.

Wait to feel the effects of cannabis before deciding whether to use more. It takes seconds to minutes to feel the effects of smoking or vaping and 30 minutes to 2 hours to feel the effects of edibles.

If you’ve never used cannabis before or have low-tolerance, start with a lower THC product. If using an unfamiliar strain or trying a new edible product, sample a small amount first and wait to see how you react.

One at a Time

Complications are more likely if you mix drugs. For example, mixing cannabis with alcohol can cause extreme anxiety, nausea, vomiting and fainting. Mixing cannabis with tobacco also increases health harms. Tobacco contains nicotine which is very addictive and can make it harder to cut down or quit.

Limit Use

Have days where you don’t use. More problems are associated with more frequent use.

Share Carefully

If sharing, hold joints or devices in a way that you can inhale the smoke or vapor without touching them to your lips, and break edibles into pieces instead of biting the product. Sharing items that have touched your lips increases the risk of spreading infections including meningitis, flu and other germs.

Be Aware of Bad Reactions and Mental Health Effects

Cannabis can lead to scary reactions like feeling paranoid or even seeing or hearing things that aren’t there. You are at increased risk if you have a personal or family history of mental health problems such as psychosis.

If you have a bad reaction and feel too high, try to remain calm, stay hydrated, eat something and find a safe place where you feel comfortable.

Stay Safe if Impaired

Cannabis impairs coordination and reaction time. The law does not allow young or novice drivers to have any cannabis or other drugs in their body when driving. Barely high is still too high.

Plan a safe ride if you’re thinking about using cannabis.

Being high can also affect your ability to operate other machinery, play sports or ride a bike.

Be Careful if Pregnant or Breastfeeding

If you’re pregnant be aware that cannabis can harm the fetus or newborn child. Speak with your health care provider if you need medicine to help with nausea. Cannabis can also be passed to the baby in breast milk. Until more is known about the short and long-term effects of cannabis on your baby, it is safest to avoid using cannabis while pregnant and breastfeeding.

Lock it Up

Eating edible cannabis by mistake can happen and may result in cannabis poisoning. To keep yourself, your friends, and younger children safe, keep your edibles in a safe place and make sure they are locked up and labelled.

More Info and Help

For more information or help, talk to your health care provider, or call:

Adapted From:


“Use Your Instincts” Downloads

Wallet Fact Sheet


Social Media Posts


Is cannabis safe to use? Facts for youth aged 13-17 years
Government of Canada | Cannabis Evidence Brief (August 2018)

Cannabis: Important things to know
Kids Help Phone

Cannabis Health Effects
Government of Canada

My Cannabis IQ
Early Psychosis Intervention Ontario Network (EPION)


Helpline Phone
24 hours a day, seven days a week
(Canada only)

The Drug & Alcohol Helpline
(Connex Ontario)