Loading articles...

Clinical scientists say youth should wait until they’re 25 before trying marijuana

Scientists are just starting to understand the effects of marijuana on the teenage brain, and while there are still many unknowns – they say they do know one thing for sure: the younger they start using it, the more it will impact their development.

Dr. Karen Leslie with The Hospital for Sick Children says studies show 10 to 15 thousand Ontario high school students smoke marijuana on a daily basis.

“So that’s a pretty concerning number, in terms of, it’s not just experimental using once ever, or once a year, it’s using every day,” she said.

Also concerning is the certainty with which physicians say adolescents are more likely to become dependent on the drug.

“We definitely know, certainly, many young people that we see in our program who have been using cannabis daily, multiple times a day, absolutely talk about and share with us that they are dependent on it,” said Dr. Leslie.

Because the frontal lobe of the brain continues to grow until most people are in their early to mid-20s, many clinical scientists are now focusing their cannabis studies on youth.

“This is a very particular time-frame in which it seems cannabis may be more dangerous,” said CAMH clinical scientist Romina Mizrahi.

Given that, Dr. Mizrahi says there’s no doubt marijuana affects the development of the teenage brain.

“Heavy use is significantly associated with increased risk of psychosis,” she said.

In her research, she’s noticed cannabis use leads to a reduction of dopamine – a neurochemical in the brain which plays a role in the motivational component of behavior. But she also found patients who experience psychosis have an increased level of dopamine in the brain.

The results have left her and her team confused.

“So I can say we’re puzzled … we just don’t know very much about it yet,” she said.

Physicians recommend waiting until the age of 25 to try it – when the brain has fully developed.

“There’s a big difference between trying, and becoming a more regular user,” said Dr. Leslie. “Absolutely the biggest message is: less is better. The least you can use, is best.”

Physicians do note there’s a huge difference between how recreational marijuana and medicinal marijuana affect youth – saying the latter can prove extremely beneficial for treating certain medical conditions.