According to a study that measured four outcomes to find the optimal age that should be recommended for recreational cannabis laws, that age is 19.
The study by Canadian researchers, published in the journal BMC Public Health, measured the outcomes of cigarette smoking, level of education reached, plus general and mental health.
Hai Nguyen, from Memorial University of Newfoundland, who is also the lead author of the new study, suggests before Canada legalized recreational cannabis use, there were strong calls from scientists and doctors to set the minimum age between 21 and 25.
“This recommendation was based on scientific evidence around the potential adverse impacts of cannabis on cognitive development,” says Nguyen. “However, policymakers feared a high minimum legal age may lead to large underground markets, with those under the legal age continuing to use cannabis illegally.
Ultimately, a lower legal age of 18 or 19 was decided across provinces, however there remains ongoing debate and calls to raise the legal age to 21.”
Many studies have shown human brains don’t completely reach biological maturity until around the age of 25.
Nguyen and his team measured the relationship between the age of commencing cannabis use and four general important life outcomes: educational attainment, cigarette smoking status, self-reported general and mental health.
The study used data from two long-term Canadian tobacco use surveys which followed nearly 20,000 Canadians for multiple years offering long-term insights into drug and alcohol use.
“Taking into account all measured outcomes, our results indicate that, contrary to the Canadian federal government’s recommendation of 18 and the medical community’s support for 21 or 25, 19 is the optimal minimum legal age for non-medical cannabis use,” says Nguyen. “Keeping the legal age below 21 may strike a balance between potential increases in underground markets and illegal use, and avoiding the adverse outcomes associated with starting to use cannabis at an earlier age.”