Pot smoked or used by 12% over a year: StatsCan

About 12 per cent of Canadians age 15 or older said they used marijuana in a year, according to Statistics Canada.

Wednesday's issue of the agency's Health Reports looks at marijuana use in 2012 compared with a decade earlier.

Among those aged 18 to 24, 33 per cent said they'd "used or tried" marijuana in the past year  — the highest prevalence by age group and the group that tended to use it more frequently. About eight per cent of 18- to 24-year-olds said they used marijuana at least once a week and nearly five per cent said they smoked or used daily.  

Marijuana is "one of the most common illicit drugs used in Canada. Significant proportions of the population report having used marijuana in the past year," said report author Michelle Rotermann, a senior researcher with Statistics Canada in Ottawa.

"When you extend it to lifetime, you get 43 per cent of the population."

Rotermann called the literature somewhat mixed on if there are negative health implications of marijuana use.

"Perhaps there are risks associated with marijuana use amongst adolescents and young adults and so were able to produce estimates," for those age groups and older.  

Use in the past year declined by nearly one-third among the youngest Canadians surveyed, 15 to 17, from 28.5 per cent in 2002 to 20.0 per cent in 2012.

In contrast, the figures changed as you got older. Past-year use among those aged 25 to 44 increased from 14 per cent to 15.6 per cent. Likewise for those 45 and older, past-year use increased from 3.0 per cent to 4.7 per cent over the decade.

Overall in 2012, about two per cent of respondents said they smoked or used marijuana daily in the previous year and another three per cent did so weekly.  

In 2012, self-reported marijuana use was highest in Nova Scotia at 16 per cent and British Columbia, 14 per cent, both above the estimates for the rest of Canada. Saskatchewan residents reported lower-than-average use at 10 per cent.

The survey did not include questions about the use of medical marijuana or the age people started using pot or other illicit use.

While self-reported marijuana use may be affected by "social desirability" bias, Rotermann said, the findings are consistent with another national survey conducted by Health Canada, the 2012 Canadian Alcohol and Drug Use Monitoring Survey.

'Evidence is clear' marijuana harmful for youth: Ambrose

The latest cross-sectional survey data was collected from 25,113 respondents participating in the 2012 Canadian Community Health Survey – Mental Health.

In a statement emailed to CBC News on Wednesday, Health Minister Rona Ambrose said the "evidence is clear" that youth smoking marijuana have an increased risk of developing mental health issues — including psychosis and schizophrenia.

"We will continue to discourage Canadians from smoking marijuana at every step," Ambrose's statement said, citing the Conservative government's national anti-drug campaign.