Annex 3 - Estimating Individual Consumption
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World Drug Report 2006 Volume I. Analysis Annex 3 - Estimating individual consumption Light tokers and chain-smokers has been found in Australia, where 60 per cent of annual users consumed the drug in the last month.265 A similar The estimated 162 million people who use cannabis do share is seen in the Netherlands (61 per cent), with not all use it at the same rate. Some of them may have slightly lower levels seen in France (52 per cent), Greece experimented with the drug once or twice, while others (53 per cent), Ireland (51 per cent), and Latvia (47 per consume the drug on a daily basis. It is estimated that cent).266 A slightly higher level is seen in the United 10 per cent of people who try cannabis will progress to Kingdom (63 per cent).267 daily use for some period of their lives, with a further 20 per cent to 30 per cent using on a weekly basis.263 This For a small share of these respondents, their use in the leaves, however, a large share of people whose use is less past month may have been the only time the drug was frequent. The prevalence of use tends to vary depending used in the past year. In other words, use in the past on the life-stage of the user. For example, about 60 per month does not mean that the drug was used every cent of French 19-year-old boys have tried cannabis, month of the previous year: ‘past month use’ does not and, of these, more than one in three uses 20 times a mean ‘monthly use’. This would suggest that the share month or more. This share drops greatly in later life of annual users that are also monthly users would be stages.264 slightly lower than the figures discussed above. On the other hand, some heavier users might, for whatever Understanding global cannabis demand requires the reason, have missed out in the previous month. Data creation of a typology of users, and the obvious source from the United States (discussed below) shows that 68 for the data on which to base this typology is household per cent of the annual respondents said they used the and school survey data. Unfortunately, while the drug 12 or more times (i.e. on average, once a month). number of ‘last-month’ users is often a feature of the In Australia, National Drug Strategy Household Surveys standard surveys, more precise questions about the have been held regularly since 1998. According to the number of days the drug was used are often lacking. 2001 data, 16 per cent of annual users over 14 con- sumed the drug every day, 23 per cent once a week or In the United States, the National Survey on Drug Use more, 12 per cent about once a month, and 49 per cent and Health (NSDUH) has been conducted regularly less often.268 Thus it would appear, if anything, that the since 1972. According to NSDUH data, of the 25 mil- number of those who say they used in the last month lion US citizens over 12 who used cannabis in 2003, may be slightly less than the number that used ‘monthly’ 14.5 million of them said they had used it in the past (12 or more times in the past year.). For the purposes of month, or about 58 per cent. This is almost exactly what this discussion, 55 per cent of the annual users will be Table 4: Breakdown of European cannabis users by frequency of use Annual per cent used 1 to 3 4 to 9 10 to 19 Country Year 20+ days Prevalence in 30 days days days days France 2000 8.4 4.4 42.5 15.5 15.5 26.4 Greece 1998 4.4 2.3 37.7 27.3 15.6 19.5 Ireland 2002/03 5.1 2.6 40.9 22.3 14.3 22.5 Italy 2001 6.2 4.7 38 30.4 12.3 19.3 Latvia 2003 3.8 1.8 57.1 24.2 13.3 5.4 Netherlands 2000/01 6.1 3.7 41.5 21.1 13.8 23.6 Portugal 2001 3.3 3.3 33.7 23.8 19.2 23.2 Spain 2001 9.7 6.8 29.5 24.8 12.1 33.6 Source: EMCDDA, Statistical Bulletin 2004. 196 2. Cannabis: Why we should care designated ‘regular’ (about once a month or more) and 16 per cent to 18 per cent seen in Australia and the US, 45 per cent ‘casual’ (less than 12 times in the previous and, as the Table below shows, they are in several cases. year). This analysis shows that survey data from a number of Comparing the US and Australian figures shows a dif- countries (the US, Australia, France, Greece, Ireland, ferent breakdown in levels of use between the two areas. Italy, and the Netherlands) indicate that past month Only a third (32 per cent) of US users said they con- users comprise about half of annual users, and that ‘daily sumed the drug less than once a month, whereas nearly or almost daily’ users comprise between 10 per cent and half (49 per cent) of the Australian users fall in this cat- 20 per cent of the annual user pool, with a mean, egory. On the other hand, 16 per cent of the Australian median, and mode of 14 per cent. users were daily consumers, compared to just 7 per cent of the US respondents. Taken at face value, Australian Sources from a wide range of countries suggest that users seem to be taken to the extremes, with US users about 14 per cent of annual cannabis users are daily more likely to fall somewhere in the middle. If the cat- users, a higher figure than many would expect. If these egories were softened a bit, however, the fit is better. For figures could be generalized to the total global popula- example, if ‘daily’ use is considered five times or more tion, this suggests that about 22.5 million people use per week, 18 per cent of the US respondents qualify, cannabis daily or near-daily, with the other 138.5 mil- close to the Australian 16 per cent. New Zealand uses a lion using it less often. This figure is important because softer standard for ‘heavy’ use: 10 or more times in the only at the level of daily or near-daily use does tolerance past month, but 20 per cent of the annual users fall into develop, and this has an impact on the amount of this category.269 cannabis used. Statistics from European household surveys as compiled How much cannabis in a dose? by the European Monitoring Centre for Drugs and Drug Addiction show rates of cannabis use among those Like all drugs, cannabis dosage is highly dependant on who used in the past 30 days. These figures show that factors such as body weight, individual metabolism, and between 1 per cent (Finland) and 7 per cent (Spain) of tolerance, and there is limited material on what consti- those who had used cannabis also consumed the drug in tutes a ‘dose’ among recreational users. There are two the last 30 days. Among past month users, between 5 ways of approaching this problem, both of which are per cent (Latvia) and 34 per cent (Spain) consumed the pursued below. One is to determine, on the basis of sci- drug more than 20 days out of the last 20, and are des- entific testing, how much cannabis a user needs to con- ignated by EMCDDA as “daily or almost daily users”. sume to receive the desired effects. Due to the extreme variability in potency, however, cannabis dosages would This figure would correspond to more than 240 days need to be expressed in the amount of THC absorbed use in the past year, close to five times a week or more by the system, rather than the weight of the product (260 days a year). Thus, we would expect the European consumed. The second approach would be to look at figures for 20+ day last month users to be close to the actual use patterns based on survey or other data. Table 5: Ratios of annual to more frequent users Share of Share of Share of annual Share of monthly Share of annual respondents users respondents who Country users that are users who are users that are who are annual are past month monthly users daily users daily users users users France 8.40% 4.40% 52% 26% 14% Greece 4.40% 2.30% 53% 20% 11% Ireland 5.10% 2.60% 51% 23% 12% Italy 6.20% 4.70% 76% 19% 14% Netherlands 6.10% 3.70% 61% 24% 15% Source: Calculations based on EMCDDA data. 197 World Drug Report 2006 Volume I. Analysis The question of what an ‘average’ user consumes is com- sumed cannabis in the last year (especially novice users) plicated by the issue of tolerance. While the extent of may have only had a toke or three on one or more occa- tolerance has not been precisely quantified, it appears to sions. The quantity consumed by these individuals in build within a few days of chronic use and dissipate just terms of the weight of the drug product is minimal. as fast.270 In other words, tolerance is not an issue for anyone but daily or near-daily users, but there are likely This level of use is reflected in the New Zealand survey to be stark differences in the dosage levels, and conse- data, which is unique in asking users how much they quently the consumption levels, between these two consumed on each occasion they used the drug, and groups.