Chapter 6 - Users and uses: form, practice, context

Patterns of use

 

Epidemiological surveys are the main method of measuring consumption patterns. These surveys cover the general population (usually 15 years of age and over) and specific populations, usually students. Most epidemiological surveys of the general population are done by telephone and based on a validated questionnaire. Personal interviews are involved in some cases. Some surveys of students are based on a questionnaire distributed in class.

Due to the low consumption of illegal drugs by the population as a whole, samples must necessarily be large (in Canada over 12,000 respondents). Whatever the sample size, these surveys inevitably underestimate consumption. Respondents tend to under-report, either because individuals simply refuse to respond because of the legal implications, or because some at-risk persons are not included in a telephone survey. Then there is the matter of memory: the more time elapsed between consumption and the survey, the less reliable one’s memory of occasions, circumstances, and quantities.

Furthermore, some reports, including the report by the French National Institute for Health and Medical Research (INSERM) and the Canadian Profile of the Canadian Centre on Substance Abuse (CCSA), use data on police and customs seizure as indirect indicators of use. We have opted to discuss data on seizures and other police and customs activities in Chapter 14. In our opinion, these data, rather than accurately reflecting use, are indicators of police drug-related activities and to some extent, market conditions.

Not all surveys measure phenomena in the same way, although, in the past two years, significant strides have been made toward improving data comparability. Generally speaking, lifetime prevalence (minimum one time consumption) is measured. This episodic or experimental consumption is distinguished from consumption within the previous year. Frequent consumption (e.g., within the past month) is less frequently measured. Heavy users are even more rarely studied. Furthermore, regular consumption tends to be measured in terms of dependency criteria - described in detail in the following chapter - rather than quantity-related indicators. As described in greater detail later in this chapter, this makes it difficult to distinguish among categories of users, specifically at-risk users and heavy users. Such information is essential to identifying target groups for preventive measures.

 

Consumption by the population as a whole

In Canada, five national surveys are the sources of data on consumption of psychoactive substances, alcohol, tobacco, and illegal drugs. The Health Promotion Survey (HPS) was conducted in 1985 and 1990; the Alcohol and Other Drugs Survey (AODS) in 1989 and 1994. The 1993 General Social Survey (GSS), a survey conducted on a regular basis, includes drug-related data. These are the data referred to in the following paragraphs.

In the 1994 survey, 23% of respondents reported consuming cannabis at least once in their lifetime. As shown in the bar graph below, men are more likely than women to have consumed cannabis, as are persons under 35 years of age.

 

 

 

 

 

Consumption varies by province. According to the AODS, consumption is highest in British Columbia (35.4%), followed by Alberta (29.4%), Manitoba (25.2%), Nova Scotia (25.1%) and Quebec (24.7%); and lowest in Newfoundland (16.3%), Ontario (16.6%) and Prince Edward Island (18.6%).

Lifetime prevalence was unchanged from the 1989 study. At the time of the Le Dain Commission, in 1970, the figure stood at 3.4%; by 1978 it was up to 17%, showing a steady increase in cannabis consumption.

Prevalence over the previous twelve months is a more sensitive indicator of current consumption as reporting is less dependant on long-term memory. The following table shows the evolution of this indicator beginning with the 1985 study.

 

 

Cannabis consumption in the last 12 months, 15 years and over[1][1]

Year	Survey	Sex       Men              Women            Total
1985   1989   1990   1993   1994	Health Promotion Survey   National Alcohol and Other Drugs Survey   Health Promotion Survey   General Social Survey   National Alcohol and Other Drugs Survey	6.9%                   4.3%                5.6%           8.9%                    4.1%                6.5%           7.0%                    3.0%               5.0%           5.9%                    2.5%               4.2%       10.1%                   5.1%                7.4%

 

 

By comparison, the percentage of users in the last year was 1% in 1970 and 9.7% in 1979.

The rate of use reported in these surveys is twice as high for men as for women. It is important to note the variations among studies. Because the AODS deals specifically with psychoactive substances, rather than being part of a broader survey of health or living conditions, it would appear to be more reliable.

We have no detailed data on incidence (i.e., new consumers) or rate of discontinuation. As will be seen further on, rising prevalence among young people would indicate increased incidence. With respect to discontinuation, it is generally believed that the vast majority of users do not continue using, although we are lacking specific information in Canada on this issue.

We are aware that there are limitations to comparing the various psychoactive substances. As properly pointed out by Dr. Zoccolillo in his testimony, each has its own characteristics and effects.

 

There is little point in comparing the levels of harm from cocaine, marijuana and alcohol. Each drug has specific kinds of harm. If you were to compare the effects of tobacco and cocaine in young people, you would conclude that cocaine is terrible but tobacco is not worth worrying about, because the harm from tobacco takes 30 years to appear. The point is that there are different patterns of harm and making comparisons among them is not a useful exercise. [2][2]

 

Nonetheless, to place the phenomenon in context, we believe it is valid to compare Canada’s consumption of cannabis in the general population to consumption of other substances. The 1994 Alcohol and Other Drugs Survey shows that, of total illegal drug consumption, cocaine accounts for less than 1%, and heroin, LSD, and amphetamines together for approximately 1%. In the case of legal drugs, alcohol consumption is about 75%, tobacco approximately 30%. The accompanying graph compares consumption of cannabis and alcohol among those over 15 years of age.

General population studies have been conducted in Ontario since 1977, giving the province the most extensive database in Canada. Of even greater interest, is the fact that Ontario (again since 1977) has conducted studies in schools. This practice provides for a better tracking of trends.

According to the 2000 report of the Centre for Addiction and Mental Health (CAMH)[3][3], more than one third (35%) of Ontarians over 18 years of age have consumed cannabis at least once in their lifetime and 10.8% within the last 12 months. The figure for users within the past year has changed little since 1984 (11.2%), although it is up slightly from the 1977 figure (8%). The 18-29 age group shows the steadiest increase, from 18.3% in 1996 to 28.2% in 2000; the 1984 figure for the cohort is 28.5%. In the long term, we also see an increase in consumption within the last 12 months in the 30-49 age group (from 6.5% in 1977 to 18.7% in 2000). The following table sets out selected data from the report.

 

 

 

 

Proportion of Ontarians 18 years old and over using cannabis users in the previous 12 months

(N =)	1977 (1059)	1982 (1026)	1984 (1043)	1987 (1075)	1989 (1098)	1991 (1047)	1992 (1058)	1994 (2022)	1996 (2721)	1997 (2776)	1998 (2509)	1999 (2346)	2000 (2406)
Total   M W   18-29 30-39 40-49 50-64 65+	8.1     11.2     4.5      22.6      3.9      2.3      1.2	8.2     12.3     4.1      22.7     4.2         1.3	11.2      15.6      7.1      28.5      9.5      2.2      1.8	9.5      12.3      6.8       20     11.6      5.4	10.5      13.0      8.2      24.6    11.8      3.9      1.4	8.7      11.5      6.0      19.9      9.1      3.0	6.2        9.1      3.6      13.3      6.6      2.4      1.3	9.0      11.4      7.0      19.6    10.2      4.3	8.7      12.6      5.3      18.3    11.3      6.1	9.1      11.4      7.0      21.4      9.8      4.3      1.7	8.6      12.1      5.4      25.2      8.2      4.      1.4	10.4      13.2      7.8      27.1    10.3      6.8      4.1	10.8      14.3      7.7      28.2    12.3      6.4      2.9

 

 

Of those who consumed cannabis at least once in their lifetime, 68% did not consume within the last 12 months, 15% consumed less than once a month, and 17% more than once a month. Of users within the last year, 47% consumed less than once a month and 53% at least once a month.

In Quebec, general population studies were done in 1987, 1992, and 1998. L’enquête sociale et de santé (ESS)[4][4] reports that 31.3% of people 15 and over used cannabis or another illegal drug at least once in their lifetime, and 13.5% had consumed cannabis at least once in the past few months. As elsewhere, consumption is a function of age: in the 15-24 age group, consumption of illegal drugs is 39.7%; it is 18.4% in the 25-44 age group, 8% in the 45-64 age group, and 5.5% in the 65 plus age group. Although 83.7% of the 45-64 age group and 93.8% of the 65 plus age group report never having used a prohibited drug, over 40% of the 25-44 age group and half (50.3%) of the 15-24 age group report current or past consumption.