Public forum held to get message out that marijuana a real threat to teens

Elizabeth Payne,

A panel discussion on the effects of cannabis use on the teen brain took place at Ben Franklin Place in Ottawa on Monday, Feb 22, 2016. Dr. Tony George was a guest speaker on the panel. Tony Caldwell / Postmedia

With legalization on the horizon, there is mounting evidence that early and frequent cannabis use can have a devastating long-term impact on teenage brains.

Researchers and officials with the Canadian Centre on Substance Abuse held a public forum and met with staff from Ottawa Public Health Monday in an effort to get the message out that marijuana is not benign, especially not for adolescents.

As marijuana moves to the front of public policy agendas in Canada and elsewhere, CCSA officials say it is important to better understand recent evidence about its impact on youth. The federal Liberal government has promised to legalize and regulate marijuana.

Because of the rapid changes in brain structure and function that occur during adolescence, “use of cannabis during this developmental period can have negative cognitive, mental health and physical effects,” according to a 2015 report from the CCSA called: The Effects of Cannabis use during Adolescence.

“We may be living in an environment where legalization is coming, but let’s not forget about youth whose brains are developing and are at risk for mental health disorders,” said Dr. Tony George, medical director of the complex mental illness program at the Centre for Addiction and Mental Health in Toronto. The Centre is calling for strict regulation, if marijuana is legalized, to keep it out of the hands of youth.

That could be a tough task. Canadian youth, according to 2009 research from the World Health Organization, use cannabis more than their counterparts in any other developed country.

Even before legalization, marijuana is the most commonly used illicit drug among Canadian youth, many of whom consider it harmless. A 2013 drug and alcohol use survey found 22.4 per cent of youth between 15-19 had used cannabis in the past year, about 2.5 times higher than adults 25 and older.

Teens interviewed in focus groups also reveal widely held beliefs that marijuana is largely harmless.

But a growing body of evidence points to serious mental and cognitive harm for some youth who use marijuana frequently. The earlier frequent use begins, the greater the potential for damage, said Dr. Andra Smith, a neuroscientist and psychology professor at the University of Ottawa.

Dr. Andra Smith was a guest speaker at a public forum on the effects of cannabis use on the teen brain. ‘Earlier is worse,’ she said. Tony Caldwell / .

“Earlier is worse, because the teenage brain is still developing and it seems like cannabis is hijacking that development. That is the problem,” she said.

“If it is going to be legalized, regulation has to be key. Just because it is legal doesn’t mean it is a benign drug.”

Not only is heavy marijuana use linked to impaired executive functioning of adolescent brains, but it can change the brain’s architecture, forcing it to work harder to complete tasks. Some research has linked teens who use cannabis at least 50 times by age 15 with lower test scores and academic performance than those who do not smoke.

Other research links heavy adolescent marijuana use to a higher risk of psychosis and schizophrenia.

Swedish research found that individuals who used cannabis more than 50 times by age 18 were six times more likely to develop schizophrenia than those who did not.

The casual relationship between marijuana and psychosis is still being researched, but it suggests individuals with a predisposition to schizophrenia might be more vulnerable to the psychosis-inducing effects of THC (tetrahydrocannabinol), the active ingredient in marijuana.

Researchers are also studying links between cannabis and mood and anxiety disorders, and other behavioural disorders.

And researchers say the detrimental effects of cannabis on driving is also an issue of growing concern.
“The key message is marijuana is not a benign subject,” said Amy Porath-Waller, director of research and policy at the Canadian Centre on Substance Abuse. “There are significant effects, whether you are looking at cognitive functioning, mental health, risk of addiction, impaired driving. The purpose of (Monday) was to convey that message.”