Skip to main content

Cannabis Use and Mental Health Risks to Youth

​​A Message from Dr. Nel Wieman


With the legalization of non-medical cannabis in Canada set to happen on October 17, 2018, we at the FNHA want to provide you with as much health-related information on cannabis as possible so you can make the best and safest choices for yourself and your family members. If you'd like to learn more in the days leading up to legalization and beyond, you can check our website for a series of messages on cannabis and health. 

In this message, I'll focus on youth and cannabis use, particularly the risks to mental health and brain development. We know that many youth have tried or use cannabis regularly, though how much and how often varies. And we know that cannabis, like alcohol, may be harmful to your health. ​What may not be so well known is that cannabis is particularly harmful to the developing (young) brain. As an Indigenous psychiatrist and advocate for the mental health of Indigenous youth, I'd like to share my concerns about this with you.

The main thing I want to emphasize is that everyone should be aware that using substances like cannabis regularly while the brain is still maturing can be associated with certain increased risks. This is because the brain is considered more vulnerable to injury (of various kinds, including substance use) as it grows and make connections between brain areas up until your mid-20s. Also, some mental health disorders typically first appear between the ages of 15-25 years. So, although there are claims that cannabis use can relieve pain and/or act as a medicine, I believe these benefits do not outweigh the risks in the case of youth.

Here is what we know from research about cannabis and mental health in young people:

​•  Regular cannabis use at a young age (under 16 years) corresponds with an increased likelihood of developing health, educational and social problems such as dropping out of school and not finishing college or university.

• Regular cannabis use at a young age, especially heavy use, can affect thinking abilities including attention span, memory and overall intelligence (IQ).

• Regular cannabis use at a young age may increase the risk of developing psychosis in those who already have some risk – e.g., if there is a history of childhood trauma or a parent or sibling who has a psychotic illness.

• Cannabis use by youth with a diagnosed psychotic illness (e.g., schizophrenia, bipolar disorder) may worsen symptoms or decrease ability to function. See sidebar.

• Cannabis use may also increase the risk of developing depression, bipolar disorder, dependency on cannabis and/or using other substances

• Cannabis with high levels of THC may worsen anxiety and panic disorder.

Given what we do know about cannabis from the research so far, we would strongly recommend to young people 25 years and younger that if they're going to use cannabis, they use it with caution and  limit their use as much as possible (e.g., use less cannabis per occasion, use less frequently, try not to use regularly/daily). ​Our overarching message to First Nations youth is that you consider delaying your first use of cannabis as late as possible.

If you have any concerns about your use of cannabis, or any mental health symptoms you think may be related to your use, please don't hesitate to speak with your health care provider.

And remember to keep checking back on the FNHA website – we will continue to provide health-related information on cannabis.  Remember, we're here to help and will meet you where you're at.

The word "psychosis" can be scary. Psychosis is a symptom and can occur in a number of different mental health disorders. Psychosis means that someone is experiencing symptoms that indicate they are not in touch with reality – e.g., hearing voices that no one else hears, seeing things that other people do not see, believing things that no one else thinks are true or are happening. ​Psychosis as a symptom can occur in mental health disorders including depression, bipolar disorder (also known as manic-depression), schizophrenia – and as a result of heavy substance use, including cannabis.

Stay up to date! Join our mailing list to get updates, news and events emailed to you.

Sign up

There was an error subscribing you. Please try again later.

You are now subscribed!