Legalizing and regulating marijuana would help – not hurt – young people who suffer from mental illness or use the drug to self-medicate, say psychiatrists and addiction experts, who argue that is the only way for the public to have an open dialogue on the harms associated with the illegal drug.
Marijuana has emerged as an issue in the federal election campaign. The Liberals promise legalization, the NDP pledge at least to decriminalize it, and the Conservatives vow further crackdowns and are using the debate to attack their opponents.
Among the Conservatives' main arguments against legalizing pot is that doing so would put youth at risk, pointing to evidence that the drug is linked to psychosis and schizophrenia.
But Elisabeth Baerg Hall, a youth psychiatrist and clinical professor at the University of British Columbia, says that if marijuana was legalized and regulated, Canadians could "really talk about the dangers," as teachers and public health officials do with tobacco and alcohol.
"The reality now is I have many, many patients in my young adult population who are self-medicating with pot," said Dr. Baerg Hall, who also runs Langara College's mental-health program.
Young cannabis users do not often have examples of what responsible or excessive consumption looks like.
"I try to say, 'Okay, we all understand alcohol is a bit of a social lubricant, so you have a glass of wine, but has anyone ever said to you, 'You're anxious and depressed so you should take five glasses of alcohol a day?' Nobody talks like that, and for a good reason," she said.
As long as pot remains illegal, young Canadians, who according to the UN, consume more cannabis than any of their peers in the industrialized world, will have no official source of information about it, says Benedikt Fischer, a senior scientist at the Centre for Addiction and Mental Health in Toronto.
"No teacher today can give any advice to young people about cannabis," said Dr. Fischer, whose organization released a framework for legalizing the drug last year. "If they say anything except, 'It's illegal, don't do it,' it could be interpreted as promoting drug use and the next day, they're sued by parents."
The Canadian Centre on Substance Abuse, funded by the government to study the use and abuse of drugs, estimated that about a quarter of teens and young adults used marijuana in 2013, which is more than two and half times the percentage of adults over 25 years old.
Last December, Health Canada spent millions of dollars on an anti-marijuana ad campaign that claimed smoking too much pot reduces the IQs of teens. Three leading national medical bodies refused to endorse it, calling it a "political" anti-pot campaign, and experts have questioned the IQ claim.
Conservative party spokesman Stephen Lecce said in an e-mailed statement that the party believes "marijuana is an illegal drug with dangerous and lasting health effects, especially on our youth."
"Protecting kids from the very real mental-health risks of marijuana such as psychosis and even schizophrenia are paramount for our Conservative government," Mr. Lecce's statement said.
Scientific evidence indicates the two conditions are linked to heavy use of the drug, but no causality has been proven, experts say.
At a North Vancouver forum on youth marijuana addiction and ADHD late last week, Anthony Ocana, a family doctor and addiction specialist, said his younger patients who have mental health issues such as anxiety or bipolar disorder will often smoke marijuana, which is easily attainable, to calm their symptoms.
Dr. Ocana told the crowd he has noticed one serious long-term harmful effect among his patients who smoke almost daily: the gradual decline of their cognitive function.
He added that psychosis is the biggest short-term risk to his patients under 25 years old that consume cannabis on more than 20 days a month. These episodes often come from doses that are too high in THC, marijuana's psychoactive substance, or mixing the drug with other substances or medicines.
Research has shown the brain develops its neuro-pathways well into a person's 20s and it is important that the full effects of cannabis use during this time are understood, Dr. Baerg Hall said.