Cannabis Health effects

Cannabis, like alcohol and tobacco, poses a number of health risks.

You should not use cannabis if you are pregnant or breastfeeding. It poses a risk to the fetus or newborn child. Heavy cannabis use has been linked to lower birth weight. There may also be other health risks associated with cannabis use during pregnancy and breastfeeding.

At any age, cannabis use affects the way the brain functions. This includes impacts on:

  • attention
  • memory
  • learning

The brain does not stop developing until around age 25. The younger you are when you begin cannabis use and the more often and the longer you use it, the more likely that it will have a bigger impact on your brain.

Substance use disorder

You should not use cannabis if you have a predisposition or family history of psychosis or problematic substance use.

Cannabis can be addictive. Close to 1 in 3 people who use cannabis will develop a problem with their use. Close to 1 in 10 people who use cannabis will develop an addiction to it. This statistic rises to about 1 in 6 for people who started using cannabis as a teenager.

Cannabis addiction can cause serious harm to your:

  • health
  • social life
  • school work
  • work and financial future

If you or someone you know is struggling with a substance use disorder with cannabis or other drugs, help is available.


Help resources in your province or territory


  • Alberta Health Services Addiction Helpline
    A 24-hour toll-free confidential service available to all Albertans.
    Toll-free: 1-866-332-2322
  • Alberta Health Services – Addiction and Mental Heatlh
    A list of programs, services and treatment facilities available in Alberta.
  • Alcohol and Drug Use in Young People
    Prevention strategies for parents and caregivers.

British Columbia

  • Alcohol and Drug Information and Referral Service
    This service is available to people across B.C. needing help with any kind of substance use issues 24 hours a day. It provides information and referral to education, prevention and treatment services and regulatory agencies.
    Toll-Free: 1-800-663-1441
    Lower Mainland: 604-660-9382
  • HealthLink BC
    HealthLink BC helps you learn about health topics, check your symptoms and find the health services and resources that you need for healthy living. Call 8-1-1 to consult with a nurse, pharmacist or dietitian or visit for easy access to help you find the health services you need, closest to where you live. Translation services are available in over 130 languages on request.
    Anywhere in B.C.: 8-1-1
    TTY (Deaf and hearing-impaired): 7-1-1
  • BC Crisis Line
    Toll-Free: 310-6789 (no area code needed)
  • Kelty Mental Health Resource Centre
    A provincial resource centre that provides mental health and substance use information, resources and peer support to children, youth and their families from across B.C.
    Toll-Free: 1-800-665-1822
    Lower Mainland: 604-875-2084
  • BC Mental Health and Substance Use Services
    Tel: 604-875-2345 or toll-free (in B.C. only)
  • Mind Check
    Designed to help youth and young adults in British Columbia check out how they are feeling and quickly connect to mental health resources and support. Support includes education, self-care tools, website links, and assistance in connecting to local professional resources.
  • Here to Help
    Provides access to information on mental health, mental disorders and substance use problems and disorders.


  • Government of Manitoba, Healthy Living and Seniors, Addictions
    Provincial Adult Addictions Information
    Toll-Free Line: 1-855-662-6605
  • Youth Addictions Centralized Intake Service
    Toll-Free Line: 1-877-710-3999
  • Addictions Foundation of Manitoba
  • Resource Assistance for Youth (RaY)
  • Mobile Crisis Services
    Winnipeg RHA – Adult Mobile Crisis Service: 204-940-1781
    Youth Mobile Crisis Team: 204-949-4777

    Interlake-Eastern RHA – Mobile Crisis Services: 204-482-5376 or toll free 1-877-499-8770

    Prairie Mountain Health – Mobile Crisis Unit: 204-725-4411

    Southern Health – East of Red River Mental Health
    Access Crisis Response Services/Warm Call line: 204-326-9276 or 1-888-617-7715

    Southern Health – West of Red River Mental Health
    Access Crisis Response: 1-866-588-1697

    Crisis Line
    24 Hour Crisis Line: 204-786-8686

New Brunswick

  • Tele-care
    Call from anywhere in New Brunswick (available 24 hours/day).
    Tel: 8-1-1
  • Addiction Treatment Services
    A branch of New Brunswick’s Department of Health.
  • New Brunswick Addiction Centers

Newfoundland and Labrador

  • Newfoundland and Labrador Helpline
    Call toll-free 24 hours a day.
    Toll-free: 1-888-709-2929
    TTY: 1-888-709-3555
  • Provincial Mental Health Crisis Line
    Toll-free: 1-888-737-4668
  • Government of Newfoundland and Labrador, Department of Health and Community Services Mental Health and Addictions
    Call: 1-709-729-3658

Northwest Territories

  • Northwest Territories Helpline
    Call toll-free from anywhere in the Northwest Territories.
    Toll-Free: 1-800-661-0844
  • Government of the Northwest Territories, Department of Health and Social Services, Addictions: where to get help

Nova Scotia

  • Government of Nova Scotia Addiction Services
    Department of Health and Wellness
    Addiction Services
  • Addiction Services Provincial Line
    Tel: 1-866-340-6700


  • Nunavut Kamatsiaqtut Help Line
    Provides anonymous and confidential telephone counselling for northerners in crisis.
    Tel: 867-979-3333
    Toll-Free: 1-800-265-3333
  • Government of Nunavut, Department of Health


  • Ministry of Health and Long Term Care, Mental Health and Addictions
  • ConnexOntario, Drug and Alcohol Helpline
    Provides free, confidential and anonymous information services about drug and alcohol addiction services in Ontario, by phone, email or web chat, 24/7/365.
    Toll-Free: 1-800-565-8603
  • Parent Action on Drugs
    Develops programs and resources for parents, youth, educators, health promoters and communities related to problematic substance use.
  • Good2Talk
    Is a free, confidential and anonymous helpline (24/7/365) for post-secondary students (17-25) in Ontario that provides professional counselling and information and referrals on mental health, addictions and well-being.
    Toll-Free: 1-866-925-5454

Prince Edward Island

  • Prince Edward Island Addiction Services
    Toll-Free from anywhere in Prince Edward Island: 1-888-299-8399
  • Health PEI


  • Ministère de la Santé et des Services sociaux
    Government of Québec website.
  • Drugs: Help and Referrals
    Call toll-free from anywhere in Quebec or locally in Montreal.
    Toll-Free: 1-800-265-2626
    Montreal: 514-527-2626
  • Tel-jeunes
    Helpline for youth. Call 24 hours/day, 7 days/week toll-free anywhere in Quebec.
    Toll-Free: 1-800-263-2266
    514-600-1002 (text messaging, from 8am to 10pm)
  • LigneParents
    Helpline for parents. Call 24 hours/day, 7 days/week toll-free anywhere in Quebec.
    Toll-Free: 1-800-361-5085


  • Government of Saskatchewan HealthLine
    Online and telephone services for adults, youth and health providers.
    Tel: 8-1-1
  • Government of Saskatchewan, Healthy Living, Alcohol, Drugs and your Health
    Information about the risks and effects of problematic drug and alcohol use.
  • Government of Saskatchewan, Mental Health and Addictions, Alcohol and Drug Services
    Directory of Alcohol and Drug Treatment Services.


  • Government of Yukon, Mental Wellness and Substance Use Services
    A 24-hour toll-free helpline from anywhere in Yukon.
    Toll-Free: 1-867-456-3838