Top of the page
Cannabis (marijuana) is a drug that is made up of the leaves, flowers, and buds of the cannabis plant. People may use cannabis for medical or non-medical reasons.
The two most active chemicals in cannabis are THC and CBD. THC affects how you think, act, and feel. It can make you feel very happy or "high." CBD can help you feel relaxed without the "high."
There are many types, or strains, of cannabis. Each strain has specific THC-to-CBD ratios. Because of this, some strains have different kinds of effects than others. For example, if a strain of cannabis has a higher ratio of THC to CBD, it's more likely to affect your judgment, coordination, and decision making.
There are many ways people can use cannabis. For example, people can:
When you use cannabis, you may be putting your health at risk.
People often use cannabis for the way it makes them feel. Using it may make them:
But it may also cause unwanted side effects, such as:
How soon and how long you may feel the effects of cannabis depends on several things, including how it was taken. For example, when cannabis is smoked, the effects can usually be felt within seconds after inhaling. On the other hand, when cannabis is eaten, the full effects may not be felt for up to 90 minutes after you eat it. Since the effects aren't felt right away, people may think they need more and use too much. To avoid this, start with small amounts until you know how edibles affect you.
How much cannabis you've used and how long you've been taking it can also affect how your body responds to it. You may feel the effects of cannabis for hours after you use it.
Long-term use of cannabis may lead to problems such as:
Using cannabis is not safe for you or your baby. If used during pregnancy, it can harm a developing baby (fetus). It can pass from the mother's blood to the baby's blood. And it can pass from the mother's breast milk to the baby during breastfeeding.
Cannabis can cause problems for you during your pregnancy and when it is time for your baby to be born. It may also affect your baby both before and after he or she is born. This is even more true for people who use a lot of cannabis.
Health Canada says that cannabis use during pregnancy may:footnote 1
THC is found in breast milk. It can cause problems with feeding. Health Canada says that babies exposed to THC in breast milk may:footnote 1
Using cannabis before the age of 25 can affect a young person's brain development, as well as emotional and social development. Some young people who use cannabis may develop cannabis use disorder. They may find it hard to control their use and keep using cannabis even though it's having harmful effects on their lives.
Cannabis affects the parts of the brain that deal with judgment, decision making, and emotions. This can make it harder for young people to think, learn, reason, remember, solve problems, and make good choices. And they may be less able to control their emotions and actions. For example, they may engage in risky behaviours like driving when "high," having unsafe sex, binge drinking, or using other drugs.
Young people who use cannabis may be more likely to have anxiety and depression than others who don't. And they may have more problems in school, relationships, and work.
Some people who use cannabis may develop cannabis use disorder. This can range from mild to severe (dependency). They may find it hard to control their use and keep using cannabis even though it's having harmful effects on their lives.
The risk of cannabis use disorder is higher in people who:
People who use cannabis often and then quit may have withdrawal symptoms. These include anxiety, trouble sleeping, and intense cravings for the drug.
Using cannabis isn't risk-free. But there are things you can do to reduce your risk of getting sick or injured.
Don't be afraid to call if you or someone you know needs medical care. The reason for the call won't be reported to the police.
CitationsGovernment of Canada (2018). Is cannabis safe during preconception, pregnancy, and breastfeeding?: Cannabis evidence brief. Government of Canada. https://www.canada.ca/en/health-canada/services/publications/drugs-health-products/is-cannabis-safe-during-preconception-pregnancy-breastfeeding.html. Accessed February 27, 2019.Other Works Consulted Holitzki H, et al. (2017). Health effects of exposure to second- and third-hand marijuana smoke: A systematic review. Canadian Medical Association Journal Open, 5(4): E814–E822. DOI: 10.9778/cmajo.20170112. Accessed July 19, 2018.Fischer B, et al. (2017). Lower-risk cannabis use guidelines: A comprehensive update of evidence and recommendations. American Journal of Public Health, 107(8): e1–e12. DOI: 10.2105/AJPH.2017.303818. Accessed July 18, 2018.Government of Canada (2018). About cannabis. Government of Canada. https://www.canada.ca/en/health-canada/services/drugs-medication/cannabis/about.html. Accessed July 18, 2018.Government of Canada (2018). Cannabis and mental health. Government of Canada. https://www.canada.ca/en/health-canada/services/drugs-medication/cannabis/health-effects/mental-health.html. Accessed July 18, 2018.Government of Canada (2018). Cannabis health effects. Government of Canada. https://www.canada.ca/en/services/health/campaigns/cannabis/health-effects.html. Accessed July 18, 2018.Government of Canada (2018). Health effects of cannabis. Government of Canada. https://www.canada.ca/en/health-canada/services/drugs-medication/cannabis/health-effects/effects.html. Accessed July 18, 2018.Porath-Waller AJ (2015). Clearing the smoke on cannabis: Maternal cannabis use during pregnancy—An update. Canadian Centre for Substance Abuse. http://www.ccsa.ca/Resource%20Library/CCSA-Cannabis-Maternal-Use-Pregnancy-Report-2015-en.pdf. Accessed July 18, 2018.
Current as ofFebruary 5, 2019
Author: Healthwise StaffMedical Review: Patrice Burgess MD - Family MedicineAdam Husney MD - Family MedicineMartin J. Gabica MD - Family MedicineKathleen Romito MD - Family MedicineMichael F. Bierer MD - Internal Medicine,
Current as of: February 5, 2019
Author: Healthwise Staff
Medical Review:Patrice Burgess MD - Family Medicine & Adam Husney MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Kathleen Romito MD - Family Medicine & Michael F. Bierer MD - Internal Medicine,
To learn more about Healthwise, visit Healthwise.org.
© 1995-2019 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.