Should there be a legal age for buying and smoking pot?

The Canadian Medical Association says Canadians under 21 shouldn't be legally allowed to smoke pot, but studies on the effects of weed on developing brains are open to interpretation

by Elianna Lev

As the clock ticks toward marijuana legalization next spring, important aspects of the Liberal government's plan remain hazy.

We have teasers about how pot will be sold - liquor stores and pharmacies might be slinging products.

But what the legal age for buying will be remains a big question, and the conflicting results of new research on marijuana's effects on the brains of young people aren't helping.

Among those eager to know more about the feds' intentions is the Canadian Medical Association, which late last month submitted a list of 22 recommendations to the Task Force on Marijuana Legalization and Regulation.

Citing the health risks associated with brain development in children and young people, the CMA says Canadians under 21 shouldn't be legally allowed to smoke pot. And the quantity and potency of the marijuana they can buy should be restricted for those under 25.

Experts believe marijuana use can change the brain before it's fully developed, which research suggests happens by the age of about 25. But the CMA acknowledges in its submission that setting the legal age at 25 would be unrealistic, since those between 15 and 24 are smoking pot at twice the rate of the rest of the population.

Setting the limit at 18, the age of majority, or younger, on the other hand, raises the spectre of Grade 12 students making extra cash by selling legally purchased Pink Kush to minor niners before the Halloween dance.

Whatever the minimum age, the CMA also proposes that it should be federally regulated, not set by the provinces, so minors won't be motivated to celebrate New Year's getting blasted in a province where the legal age is lower.

Zachary Walsh, assistant professor of psychology at UBC Okanagan, whose research focuses on cannabis, argues that the legal age should be set by deciding when young Canadians are mature enough to make choices that involve their health rather than when their brains are said to be fully developed.

He says the effects of pot on developing brains are comparable to or smaller than those of alcohol.

Certainly, the research on pot and young minds is open to interpretation. Imaging studies of the drug's impact on brain structure in humans, rather than lab rats, have offered conflicting results.

According to the U.S. government's National Institute on Drug Abuse, frequent pot smoking in the teenage years can lead to "altered connectivity and reduced volume of specific brain regions involved in a broad range of executive functions like memory, learning and impulse control."

But other studies have not found significant differences in brain structure between users and non-users of marijuana.

One of these, Association Between Lifetime Marijuana Use And Cognitive Function In Middle Age (published in the Journal of the American Medical Association), surveyed 5,115 young adults over a 25-year period and found that "cumulative lifetime exposure to marijuana was associated with lower scores on a test of verbal memory but did not affect other cognitive abilities like processing speed or executive function."

A large study from New Zealand found that adolescents who smoke regularly stand a greater chance of having lower IQs by mid-adulthood.

But the results of two studies of twins, Impact Of Adolescent Marijuana Use On Intelligence, showed no negative link between pot use and IQ. The authors of that report say IQ declines in adolescence are just as likely to have resulted from genetics and family environment.

While there's some evidence that smoking marijuana leads to poorer cognitive performance and a greater chance of early psychosis for some people prone to mental illness, Walsh says the research findings don't apply to all users.

"We know it doesn't universally lead to bad outcomes, but we certainly want to protect young people from as much risk as we can," he says.

Brain matter aside, how do we formally decide when a young adult Canadian has reached maturity? In Colorado and Washington, the legal age to buy weed - 21 for both states - was determined by referendums.

Morgan Fox, with the Washington, DC-based Marijuana Policy Project, says settling on 21 was a logical and simple conclusion stateside.

"We are trying to regulate marijuana similarly to alcohol, and people are comfortable with that cutoff," he says. Fox adds that any attempt to make 18 the legal age would lead to "no end of grief from opponents saying high school seniors would be buying it for their friends."

Eighteen is the legal age to purchase marijuana in the Netherlands, where buying it is illegal except in coffee shops with a permit.

Piet Hein van Kempen, a criminal law professor at Radboud University, says the legal age was little discussed when the Netherlands legalized. The government figured citizens could buy alcohol, vote and purchase a home and car at 18, so why not pot?

While our feds mull that issue over, Eugene Oscapella, who teaches drug policy in the criminology department at the University of Ottawa, says they should also be working on ways to make talking about marijuana and its possible dangers less taboo if they're serious about keeping it out of the hands of people under 21.

"As long as people are motivated to use it, telling them they can't until they're 19 or 21 won't do it," Oscapella says. "It's not just about setting a strict legal limit. You have to get into why people want to use it."