Health expert warns of lack of awareness about effects of pot

A national health care expert says there are Canadians who are unaware of the effects of cannabis on mental health — with concerns growing ahead of the drug's summer legalization.

Cannabis users living with a mental illness have a greater risk of developing a psychotic episode, said Chris Summerville, CEO of the Schizophrenia Society of Canada.

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Summerville said the risk of developing psychosis is multiplied by five to seven times. It's even greater for people under the age of 25 who are still developing.

"People should be making informed decisions about the use of cannabis. You're at higher risk if you have mental health problems or if mental illness is in your family background," he said. "It can trigger psychosis leading sometimes to full-blown schizophrenia."

Summerville said that a cannabis user's brain receptors and neurotransmitters can be affected by the amount of THC, the main mind-altering ingredient in cannabis, which would ultimately impact development.

"It can lead to depression, anxiety, suicidal ideology and it can cause psychosis," he said.

The problem is, many users don't know how they're being affected, he said.

'Not ready for legalization'

Summerville, who's also the co-chair of the Canadian Alliance on Mental Illness and Mental Health, is worried that both users and the general public aren't informed about the impact of cannabis on the mind and body.

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"We are not ready for the legalization of cannabis," he said.  "We are not ready in terms of disseminating information related to the risk of using cannabis. The public is uninformed about the risk in terms of mental health problems."

He said the public is also exposed to many myths about drug-use.

"There is a lack of resources out there so people can make good informed decisions," he said.

Increase in mental illness

In December, a Toronto lawyer from a high-profile family attacked a St. Thomas family with a baseball bat while suffering from a cannabis-induced psychosis, says his lawyer.

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Mark Phillips was given a conditional discharge on Tuesday.

Summerville said more people may experience episodes stemming from mental illness if they aren't well-equipped with the tools to make informed decisions about cannabis-use ahead of its legalization.

"There will be an increase in mental illness whether that's manifested through depression, anxiety or suicidal ideations," he said.

He said much of this can be prevented with more education through health and community services.

However, he's worried large pockets of people — especially vulnerable populations — may not be educated in time for the fast-approaching legalization deadline.