Prevalence and correlates of marijuana use in Canada, 2012

by Michelle Rotermann and Kellie Langlois

According to the 2012 Canadian Community Health Survey–Mental Health (CCHS–MH), 12.2% of Canadians aged 15 or older (3.4 million) used marijuana in the past year. In Canada, as in many other countries, marijuana is the most commonly used illicit drug.Note 1-4 A dose-response relationship has been observed  between the frequency of marijuana use during adolescence and reduced cognitive functioning, educational attainment, longer-term personal disadvantage, and marijuana dependence.Note 3,Note 5-7    Daily users are at the highest risk of experiencing negative outcomes.Note 7 There is a growing consensus that marijuana use can harm developing adolescent brains.Note 8-10 The association between marijuana use and mental illness is less clear.Note 7-9 Estimation of the potential risks and the decision to use marijuana is further complicated because some countries, including Canada, allow marijuana to be authorized for medical purposes.Note 11  Other research has suggested that an individual’s perception of risk may be reduced in places with medical marijuana laws.Note 12

This analysis investigates the prevalence of, and factors associated with, past-year and lifetime marijuana use by the household population aged 15 or older in 2012. Estimates for 2012 are compared with those for 2002 (see The data).

Past-year users more likely to be young and male

A third (33.3%) of 18- to 24-year-olds reported using marijuana in the past year.  This exceeded the prevalence of use reported by people in other age groups: 20.0% at ages 15 to 17, 15.6% at ages 25 to 44, 6.7% at ages 45 to 64, and 0.8% at age 65 or older (Table 1). In all age groups except 15 to 17, males were more likely than females to report past-year use.

In 2012, 16% of Nova Scotians and 14.5% of British Columbians reported using marijuana in the past year, significantly above the estimates for the rest of Canada (other provinces combined).  At 10%, Saskatchewan residents had lower-than-average use. Past-year use was also higher than the corresponding estimates for the rest of Canada for males in Nova Scotia and for females in British Columbia.

People living in rural areas were less likely than residents of population centres to report past-year use of marijuana.

The prevalence of past-year use did not differ by household income among males; among females, the prevalence of past-year use was lower for those in the highest income households.

Frequency of use among past-year users

The frequency of marijuana use has been related to risk of addictionNote 6,Note 7 and to reduced academic achievement among youth.Note 5-7 Daily use in the previous year was reported by 1.8% of the population aged 15 or older, and another 3.2% reported at least weekly use (one or more times a week) (Table 2). Daily use was twice as common among males as females (2.4% versus 1.2%), and more common at ages 18 to 24 (4.9%) than among younger and older people.  As well, 41% of past-year users reported that there had been a time in their lives when their marijuana use was greater than that in the last year (data not shown).

Lifetime use

An estimated 43% of Canadians aged 15 or older have tried marijuana, and 33.5% used it more than once (Table 3). Marijuana use depends on factors that include access and/or availability, perception of risk, family, and peers.Note 1,Note 2,Note 4,Note 13

According to the 2012 CCHS-MH, 53.7% of 18- to 24-year-olds and 53.5% of 25- to 44-year-olds had ever used marijuana. This was significantly higher than the percentages in other age groups: 45.7% at ages 45 to 64, 25.0% at ages 15 to 17, and 13.1% of seniors.

Despite differences in survey design, response rates and modes of data collection,Note 14,Note 15 the 2012 CCHS—MH past-year and lifetime estimates of marijuana use were generally similar to estimates from the 2012 Canadian Alcohol and Drug Use Monitoring Survey.Note 16

Changes since 2002

In both 2002 and 2012, the overall prevalence of past-year marijuana use among Canadians aged 15 or older was stable at around 12% (Table 3). However, trends differed by age. Past-year use declined by nearly one-third in the 15-to-17 age group, remained unchanged at ages 18 to 24, and increased at ages 25 to 44 (from 14.0% to 15.6%) and at age 45 or older (from 3.0% to 4.7%). Most past-year users—93% in 2002 and 94% in 2012—reported using more than once in the previous 12 months (data not shown).

Between 2002 and 2012, the percentage of males who had ever used marijuana rose from 47.0% to 49.4%; excluding one-time users, the increase among males was from 37.5% to 40.1%. Use among females remained around 36% for lifetime users overall and 27% for repeat users.

Over the 10 years, the percentage who ever used marijuana fell among 15- to 17-year-olds and 18- to 24-year-olds, remained stable among 25- to 44-year-olds, and increased among older age groups. Some of the increase in lifetime prevalence, especially at ages 45 to 64, may simply reflect aging of the cohort who were in the 25-to-44 age group in 2002.

Majority who used other drugs have used marijuana

The vast majority of Canadians who have used other illicit drugs (such as cocaine, hallucinogens and heroin) have also used marijuana: 97.4% in their lifetime and 85.1% in the past year (Table 4). This association also held among people who reported lifetime non-medical use of psychotherapeutic pharmaceuticals (such as sedatives, stimulants and opioid analgesics).

By contrast, the majority of marijuana users have not used other illicit drugs and/or psychotherapeutic pharmaceuticals (lifetime and past-year). Because the survey did not ask respondents’ age at initiation for each drug used, it is not known if marijuana use preceded or followed the use of the other drugs.

Summary

In 2012, 43% of Canadians reported that they had used marijuana at some time in their lives, and 12% reported using it in the past year. Marijuana use was more common among males than females. People aged 18 to 24 had the highest prevalence of past-year marijuana use, and tended to use it more frequently than did people of other ages. At more than 50%, the prevalence of lifetime marijuana use was highest among 18- to 24-year-olds and 25- to 44-year-olds. Between 2002 and 2012, the percentage of 15- to 17-year-olds reporting past-year use declined. The prevalence of past-year use remained stable among 18- to 24-year-olds and rose slightly at older ages.

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