Almost a third of the country's teens have toked in the past three months
In October, Canada became the second country in the world to make it legal for adults to buy, grow and consume small amounts of marijuana. But it also made it a crime to give pot to anyone younger than 19 or 18, depending on the province, which led Jenny Hanley, an addictions counselor to exclaim, “It’s been proven the brain doesn’t stop growing until you are 25, and yet we’re legally selling it to people at 19. What the hell is our government thinking?”
The Canadian government has begun an $83 million public education campaign that warns of pot’s dangers. Much of the campaign targets Canadian youths, who already use more pot than young people anywhere else in the world, according to a 2013 UNICEF report. And a recent Canadian census bureau report found that 32.7 percent of teenagers had smoked marijuana in the previous three months.
But there is continuing debate about the dangers and long-term effects of pot use during adolescence, as the New York Times outlined.
“Studies have shown that marijuana use in adolescents can impair brain function for some time after the cannabis has left their bodies, and a concern raised by some experts is that many adolescents use cannabis to self-medicate for anxiety or depression,” the Times said. “Most scientists agree the risk to young brains is greatest for those who start smoking at age 12 or younger, smoke regularly and choose high-potency marijuana.”
Smoking is also dangerous for young people with family histories of serious mental illness, like schizophrenia or bipolar disorder, the newspaper said.
But for young people who start lightly experimenting with the drug at a later age, the risks of long-term damage to their growing brains are reduced.
“It’s a reasonable statement to say it could have impact on the developing brain,” said Matthew Hill, a neuroscientist with the University of Calgary who has studied cannabinoids for 18 years. “That’s not the same thing as saying it definitively will.”
While some studies found that regular cannabis use by adolescents changed brain structure and long-term cognitive functioning, follow-up studies disputed those findings and concluded that alcohol use, cigarette smoking and family background were the main drivers in I.Q. reduction.
A recent analysis of 69 studies on young, frequent cannabis users, published in JAMA Psychiatry, found that the negative effects on cognitive functioning dissipated after 72 drug-free hours.
“Cannabis is correlated with lots of things,” said James MacKillop, the co-director of McMaster University’s medicinal cannabis research center in Hamilton. “Teasing out whether it’s causally related is a much more complicated thing.”
“If you are using cannabis when you are 12 or 13, then there are probably lots of other things going on,” he continued. “There might be poor parental oversight, more early life stress or family disorganization.”
While drug prevention programs have their place, at lease one expert emphasized that good parenting is vital in rearing drug-free kids. Rebecca Haines-Saah, an associate professor of public health at the University of Calgary, who studies teenage cannabis use and harm prevention, urged parents to talk to their children early and regularly about the consequences of all substances, including caffeine, the Times said.
“If we aren’t honest with kids, they will find the information elsewhere,” Haines-Saah said.