Canada's Legal Age for Cannabis May Be Protecting Youth From Hospitalizations | Research

The takeaway

After cannabis legalization in Canada, cannabis-related hospitalizations dropped 34% among youth below the minimum legal age while continuing to rise among adults above it.

Policymakers setting cannabis age restrictions, public health researchers evaluating legalization outcomes, harm reduction advocates.

34% fewer cannabis hospitalizations among youth below the legal age, 3.5 years after legalization

What the researchers found

Cannabis-related hospitalizations declined by 2% per quarter among individuals below the minimum legal age after legalization, while no slope change occurred for those above the MLA. By 3.5 years post-legalization, hospitalizations were 34% lower for those below the MLA relative to those above it.

Why it matters

This is one of the first large-scale studies to show that minimum legal age laws for cannabis may actually work as intended, reducing harm among youth while the same harms increase among the adult population with legal access.

The numbers in context

14.6 million individuals in 2018; 137,901 cannabis-related hospitalizations during study period; 34% relative reduction below MLA at 3.5 years post-legalization (RR 0.66, 95% CI 0.49-0.91); pre-legalization rates were increasing 2% per quarter for both groups.

How the study worked

Population-based controlled interrupted time series study examining all cannabis-related hospitalizations in Canada for individuals aged 15-44 (n=14.6 million in 2018) from January 2015 to March 2022, comparing trends above and below varying provincial MLAs.

What this study cannot tell us

Observational design cannot prove causation. Cannot distinguish whether reduced youth hospitalizations reflect less use, safer use, or shifts in healthcare-seeking behavior. Provincial MLA variations could introduce confounding. Hospitalization data may undercount less severe cannabis-related harms.

How to read the evidence

Strong: Large population-based study (14.6 million) with a rigorous controlled interrupted time series design that leverages natural policy variation across Canadian provinces.

When this study was published

Published in 2025 with data through March 2022.

The bigger picture

This study provides evidence that cannabis age restrictions can be effective public health tools, similar to alcohol and tobacco age laws. The finding that adult hospitalizations continued rising post-legalization adds nuance to the legalization debate.

Questions still open

What is driving the continued increase in adult hospitalizations? Are the youth reductions sustained beyond 3.5 years? Would a higher MLA (such as 25) produce even greater reductions?

Common questions

Why did youth hospitalizations go down while adult hospitalizations went up?

The minimum legal age created a regulatory barrier for youth that did not exist before legalization. Meanwhile, adults gained easier legal access to cannabis, which may have increased use and associated harms in that group.

Does this mean legalization is good for youth?

The study suggests that age restrictions within a legalization framework can reduce cannabis-related hospitalizations among youth. However, it does not address all potential harms, and the continued rise among adults shows legalization has trade-offs.

Read the original research

Minimum Legal Age of Nonmedical Cannabis Purchase Laws and Cannabis-Related Hospitalizations in Canada, 2015 to 2022.

American journal of public health, 115(7), 1166-1174

View on PubMed ↗Publisher’s paper ↗

Citation

Myran, Daniel T; Talarico, Robert; Pacula, Rosalie Liccardo; Xiao, Jennifer; Manuel, Doug; Hobin, Erin; Konikoff, Lauren; Tanuseputro, Peter; Taljaard, Monica. (2025). Minimum Legal Age of Nonmedical Cannabis Purchase Laws and Cannabis-Related Hospitalizations in Canada, 2015 to 2022.. American journal of public health, 115(7), 1166-1174. https://doi.org/10.2105/AJPH.2025.308090