10/09/2014 06:23 EDT | Updated 12/09/2014 05:59 EST

CAMH calls for legalization of marijuana

Marijuana should be legalized with strict controls to curb its use and social harms, the Toronto-based Centre for Addiction and Mental Health says.

Canada’s current system of cannabis control fails to prevent or reduce harms associated with its use, Dr. Jurgen Rehm, director of social and epidemiological research at CAMH, said Thursday as the hospital released a new policy document on the drug.

"Cannabis sales should be regulated," Rehm said in an interview with CBC Radio’s Metro Morning.

"There should be a government monopoly on sales. There should be a minimum age for purchase and  consumption. There should be controls on availability. There should be … a ban on marketing, advertising and promotion and plain packaging."

Rehm estimated that about 40 per cent of Canadians have used pot at least once in their lifetimes, and 10 per cent have done so in the past year. But its use is associated with harms to health, including:

- Respiratory diseases such as lung cancer.

- Problems with healthy development from high levels of use by youth.

- Risk of death or injury from motor vehicle collisions.

- Dependence and mental-health problems.

Given the risk of harm, CAMH believes any reforms on marijuana control need to include a strong focus on prevention and harm reduction interventions.

Anyone who buys pot in criminal markets doesn't know about its potency or quality. Meanwhile, enforcement of cannabis laws costs Canadians $1.2 billion a year, the centre said.

While decriminalization has some advantages over prohibition, it doesn’t address health harms of cannabis use as strict regulations would, Rehm said, adding the strict regulations proposed set the model apart from other legalization approaches, such as in the U.S.  

In May, the Canadian Public Health Association also issued a policy statement saying "Canada needs a public health approach to managing illegal psychoactive substances that de-emphasizes criminalization and stigma in favour of evidence-based strategies to reduce harm."

Ian Culbert, the group’s executive director, said a different approach is needed than the current "war on drugs."

 "Canadian society isn't overnight going to embrace this idea of legalization and regulation, so it's a conversation that we have to have," he said.

CAMH’s recommendations also included:

- A framework to address and prevent cannabis-impaired driving.

- Better access to treatment.

- Investment in education and prevention.

Experts from CAMH started to develop the new policy framework last year.