Canadian Paediatric Society review linked adolescent cannabis to brain damage, dependence, mental illness, and declining academic performance

What the researchers found

Cannabis is the most common illicit drug used by Canadian teenagers. The review found that adolescent cannabis use can cause functional and structural changes to the developing brain, leading to damage. Strong associations were documented with cannabis dependence and other substance use disorders, initiation and maintenance of tobacco smoking, depression, anxiety, psychosis, impaired neurological development, cognitive decline, and diminished school performance and lifetime achievement.

The review also noted that rates of acute medical care and hospitalization for younger children who accidentally ingest cannabis are increasing, adding a pediatric safety dimension.

With Canada debating cannabis regulation at the time of publication, the review emphasized that appropriate safeguards for children and youth are vital public health priorities.

Why it matters

This review from a national pediatric society represents the consensus medical view on adolescent cannabis risk. Published just before Canada legalized cannabis, it aimed to ensure that youth protection measures were incorporated into the regulatory framework.

The numbers in context

Cannabis: most common illicit drug among Canadian teenagers. Associations: dependence, tobacco initiation, depression, anxiety, psychosis, cognitive decline, academic underperformance. Accidental pediatric ingestions: increasing.

How the study worked

Clinical review from the Canadian Paediatric Society summarizing evidence on cannabis effects in children and adolescents, published in the context of Canada's upcoming legalization.

What this study cannot tell us

Narrative review from a medical society, which may reflect a conservative perspective. Does not provide detailed risk quantification or distinguish between levels of use. May not adequately address potential benefits of reduced criminalization for youth. The review predates legalization outcomes that could validate or challenge its concerns.

How to read the evidence

Policy-relevant review from a national medical society. Provides a strong summary of pediatric concerns but represents a particular perspective on the evidence.

When this study was published

Published in 2017, just before Canada legalized cannabis in 2018. Post-legalization data has since become available.

The bigger picture

The timing of this review, published as Canada prepared to legalize cannabis, makes it a policy-relevant document. It argues that legalization must include robust protections for youth, including age restrictions, packaging requirements, public education, and treatment resources. Whether Canada's subsequent legalization adequately addressed these concerns remains debated.

Questions still open

• Did Canadian legalization include adequate youth protections? Have youth cannabis use rates changed since legalization? Would harm reduction approaches be more effective than abstinence-focused messaging for adolescents?

Common questions

Read the original research

Cannabis and Canada's children and youth.

Paediatrics & child health, 22(2), 98-102

Citation

Grant, Christina N; Bélanger, Richard E. (2017). Cannabis and Canada's children and youth.. Paediatrics & child health, 22(2), 98-102. https://doi.org/10.1093/pch/pxx017

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