Quebec says it plans to hold a series of public consultations starting this summer on how to handle the legalization of cannabis in 2018.

Ottawa has already tabled its bill legalizing the drug, but it will be up to the provinces to decide how it will be implemented.

Youth and Public Minister Lucie Charlebois explained in a news conference Monday that there will be three different consultations between now and this fall.  

"We're going to have some international experts and we're going to have people from places where it's already legalized," said Charlebois.

The first consultation take place on June 19 and 20, when experts on the issue of marijuana will be heard including psychiatrists and law enforcement experts. Those consultations will also include people from countries where the drug is already legal to discuss what works and what doesn’t.

In late August and September, regional consultations will be held to hear from the population at large. Charlebois said she also wants to make sure Indigenous voices will be heard.

Finally, there will be a web consultation in the fall.

"We don't have any choice, we've got to be ready" said Charlebois.

"If we're not ready somebody else from some other province is going to sell cannabis here, so I want to be able to protect our population."

Psychiatrists urge ban until age 21

Charlebois laid out those plans as the legalization of recreational marijuana usage is coming under the scrutiny of Quebec’s psychiatrists.

The Quebec Association of Psychiatric Physicians argues that based on their clinical experience, the bill is not acceptable in its current form and will expose young people to major mental health risks.

AMPQ President  Karine J. Igartua says scientific research shows that the human brain continues to grow until about age 25 and that regular cannabis use during this very sensitive period of brain maturation includes enormous risks.

"When you expose a growing brain to cannabis you actually change the way it grows and matures," said Igartua.

These risks, she says, include deficits in attention, memory, speed of information processing and intelligence.

Igartua pointed out that in many cases, medical imaging showed brain lesions caused by tetrahydrocannabinol (THC), a component of cannabis.

"You can actually see the thinning of the white matter in the brain," said Igartua.

She said the risk of psychosis increases by 40 per cent for all those who have used cannabis in their lifetime and that consumption can precipitate the onset of the disease.

In other words, one out of five marijuana smokers runs the risk of having a psychotic illness.

According to the doctors’ opinions, authorizing the purchase of cannabis at 21 instead of 18 years old would allow a better balance to be struck between reducing the harms caused by the illicit market and protecting future generations.

The AMPQ is also proposing to determine a maximum level of THC for any cannabis product legally sold in Canada, and to clearly indicate it on the packaging. It also suggests prohibiting any form of advertising aimed at promoting the consumption of cannabis and imposing neutral packaging.

The group also hopes to create an educational program in school, starting at the beginning of high school, on the consequences of taking drugs.

Marijuana is expected to be legal across Canada by July 1, 2018.

Ottawa is asking the provinces to regulate matters including distribution, taxation and security.