Cannabis and your health

Can cannabis affect my physical health?

Yes, cannabis can affect your physical health. Some short and long-term health effects of cannabis include¹:

Damage to the lungs from inhaling or vaping cannabis can lead to irritation of the respiratory system, shortness of breath, chronic cough, bronchitis-like symptoms, lung infections, and an increased risk for certain cancers (ex. lung cancer).
Increased risk of developing severe nausea and repeated vomiting, known as cannabinoid hyperemesis syndrome (CHS) (PDF) or cyclical vomiting, which can last for 24 hours or more and sometime requires emergency medical attention.
Difficulty conceiving due to changes in menstrual cycle, changes in hormone levels, and changes in sperm function and decreased sperm count.
Increased heart rate and changes in blood pressure, which can increase the risks of cardiac events or stroke, especially in people with pre-existing medical conditions.
Impaired cognitive functions leading to mood swings, memory loss, confusion, and decrease in attention-span and concentration.
Increased risk of falls, injuries and accidents due to decreased co-ordination of movement, balance, posture, and reaction time are also affected by cannabis use.
Cannabis use disorder and/or cannabis addiction.

There are risks with any unregulated drug produced, and cannabis is not exempt. Cannabis that is sold illegally is not subject to health and safety standards. This drug may be contaminated with pesticides, toxic fungi, or other drugs.

Can cannabis affect my mental health ?

Yes, cannabis can affect your mental health. For some people, cannabis can cause confusion, difficulty with memory, or feelings of paranoia, especially with higher THC levels.

Frequent cannabis use (daily or almost every day) has also been linked to an increased risk of²:

depression
anxiety disorders
suicide
psychosis and/or schizophrenia

In fact, research has shown that cannabis use can increase the risk of developing psychosis or schizophrenia in some people, particularly those who²:

start using cannabis before the age of 16,
have a personal or family history of psychosis and/or schizophrenia,
use cannabis frequently (daily or almost every day).

In 2023, the Lower-Risk Cannabis Use Guidelines for Psychosis (LRCUG-PSYCH) (Laboratoire de Recherche Didier Jutras-Aswad) were released. This document provides evidence-based background information about psychosis and mental health risk factors along with recommendations surrounding health promotion and psychosis-related prevention.

Cannabis Use Disorder

Contrary to popular belief, people can become addicted to cannabis. Research shows nearly 10% of people who use cannabis will develop an addiction. For people who use cannabis daily, the risk of addiction is 25% to 50%.³

Addiction to cannabis, also known as Cannabis Use Disorder (Health Canada), is diagnosed when a person has a dependency on cannabis which has resulted in significant physical, mental, and social problems.

You may be using cannabis in a problematic way if your use leads to you:

failing to fulfill major duties at work, home, or school
giving up important social, work-related, or enjoyable activities because of cannabis use
using cannabis in greater amounts or more often than intended
being unable to cut down on or control cannabis use

If you are concerned about your cannabis use or that of someone you care about, help is available.

Visit our resource on community programs, supports.
Visit mental health and addictions services Ontario (ConnexOntario). It offers services by phone, online chat, and email, and provides a directory of support services.
Reach out to your health care provider.
Crisis services are available 24/7, call Health Sciences North Crisis Services at 1.877.841.1101 (toll-free) or visit crisishelp.ca.
Learn more about cannabis (Health Canada).

Health impacts for youth

The younger someone is when they begin using cannabis the higher the chances are of experiencing negative physical and mental health effects, especially if cannabis is used before the age of 16^2,4. Mental health and cognitive impacts on youth are more common and severe because the brain is still developing until the age of 25⁴.

For more information on youth and the effects of cannabis visit our webpage on youth and cannabis.

Health impacts for pregnant and breast/chestfeeding people

Using cannabis while pregnant can have negative effects on the fetus as well as some risks for longer-term cognitive, behavioural and mental health for children exposed to cannabis during pregnancy. Additionally, using cannabis frequently during pregnancy has been linked to health issues and complications⁵.

Cannabis and its active components (THC and CBD) pass through breast/human milk while breast/chestfeeding and can affect your infant⁵.

For more information on cannabis use during pregnancy and breast/chestfeeding visit our webpage on cannabis: preconception, pregnancy, and breast/chestfeeding.

What are the known benefits of using cannabis?

There is evidence of therapeutic uses and benefits of cannabis or its component chemicals (cannabinoids). The most common medical reason for people to use cannabis is to help treat and manage pain⁶. Although cannabis can be used for health benefits, decisions as to whether cannabis is appropriate to treat an individual’s symptoms are best made in consultation with a health care provider. Learn more about accessing cannabis for medical purposes (Health Canada).

Canadian Centre on Substance Use and Addiction (CCSA). (2022a). Clearing the smoke on cannabis: Highlights. https://www.ccsa.ca/clearing-smoke-cannabis-highlights
Health Canada. (2018, March 6). Cannabis and mental health. https://www.canada.ca/en/health-canada/services/drugs-medication/cannabis/health-effects/mental-health.html
Health Canada. (2023, March 14). Addiction to cannabis. https://www.canada.ca/en/health-canada/services/drugs-medication/cannabis/health-effects/addiction.html
Get Sensible. (2021). Cannabis in context. Canadian Students for Sensible Drug Policy. https://getsensible.org/wp-content/uploads/2021/11/Sensible-Cannabis-Education-Booklet-3.pdf
(2022b). Clearing the smoke on cannabis: Cannabis use during pregnancy and breastfeeding. https://www.ccsa.ca/clearing-smoke-cannabis-cannabis-use-during-pregnancy-and-breastfeeding
Bear, D. (2023). Cannabasics: A primer for health and social service providers. Canadian Public Health Association. https://substanceuse.ca/sites/default/files/2023-11/SURE_Cannabasics_FINAL.pdf

This item was last modified on September 10, 2024