Cannabis continues to be the most widely produced and trafficked plant-based illicit drug worldwide (CND, 2006).
Large-scale production of cannabis resin is concentrated in a few countries, in particular Morocco, but also Pakistan and Afghanistan. Total global production of cannabis resin is estimated to be 7 400 tonnes annually (CND, 2006). Most cannabis resin consumed in the EU originates in Morocco; it is smuggled mainly via the Iberian Peninsula, although the Netherlands seems to represent a secondary distribution centre for further transport to EU countries. Cannabis cultivation in Morocco was surveyed for the second time in 2004, and the findings revealed a 10 % decline compared with 2003, largely as a result of intervention by the government. In 2004, the total area under cultivation amounted to 120 500 hectares in the Rif region, which corresponds to a potential production of 2 760 tonnes of cannabis resin (UNODC and Government of Morocco, 2005).
Drug seizures in a country are usually considered an indirect indicator of the supply and availability of drugs, although they also reflect law enforcement resources, priorities and strategies, as well as the vulnerability of traffickers to national and international supply reduction activities, and reporting practices. Quantities seized may fluctuate widely from one year to the next, for example if in one year a few of the seizures are very large. For this reason, the number of seizures is sometimes a better indicator of trends. In all countries, the number of seizures includes a major proportion of small seizures at the retail (street) level. Where known, origin and destination of drugs seized may indicate trafficking routes and producing areas. The price and purity/potency of drugs at retail level are reported by most of the Member States. However, data come from a range of different sources, which are not always comparable, making accurate comparisons between countries difficult.
Other countries also mentioned in 2004 as source countries for the cannabis resin seized in the EU include Albania, Portugal, Senegal, Afghanistan, Pakistan and countries in Central Asia (Reitox national reports, 2005; WCO, 2005; INCB, 2006a).
Global potential herbal cannabis production was estimated at over 40 000 tonnes in 2003 (CND, 2005), with source countries throughout the world. Herbal cannabis seized in the EU in 2004 is reported to have originated from a variety of countries, mainly the Netherlands and Albania, but also Angola, South Africa, Jamaica and Thailand (Reitox national reports, 2005; WCO, 2005; INCB, 2006). In addition, local (indoor or outdoor) cultivation and production of cannabis products takes place in most of the EU Member States.
Worldwide, a total of 1 471 tonnes of cannabis resin and 6 189 tonnes of herbal cannabis were seized in 2004. Western and Central Europe (74 %) and South-west Asia and the Near and Middle East (19 %) continued to account for most cannabis resin seized, while quantities of herbal cannabis seized remained concentrated in North America (54 %) and Africa (31 %) (UNODC, 2006).
In 2004, an estimated 275 000 seizures of cannabis resin amounting to 1 087 tonnes were made in the EU. Most seizures continued to be reported by Spain (which accounts for about half of all seizures and for about three-quarters of the total quantity seized in the EU), followed by France and the United Kingdom (40). Although the number of resin seizures in the EU as a whole declined between 1999 and 2003, trends in reporting countries indicate an increase at EU level in 2004 (41). The total amount of resin intercepted in the EU shows a continuous increase over the period 1999–2004, although in 2004 a majority of countries (but not Spain) reported a decline (42).
Herbal cannabis is less seized in the EU; in 2004 there were an estimated 130 000 seizures, amounting to 71 tonnes, with most seizures occurring in the United Kingdom (43). The numbers of herbal cannabis seizures in the EU have increased consistently since 1999 (44), although the quantities seized have been decreasing in reporting countries since 2001 (45). This picture is preliminary as data from the United Kingdom for 2004 are not yet available.
In 2004, an estimated 12 800 seizures in the EU and candidate countries resulted in the recovery of about 22 million cannabis plants and 9.5 tonnes of cannabis plants, with Turkey accounting for the greatest quantities seized (46). The number of seizures of cannabis plants has increased since 1999 and, based upon data from reporting countries, continued to increase in 2004.
In 2004, the average retail price of cannabis resin in the EU varied from 2.3 euros per gram in Portugal to over 12 euros per gram in Norway, while the price of herbal cannabis ranged from 2.7 euros per gram in Portugal to 11.6 euros per gram in Malta, with a majority of countries reporting prices for cannabis products of between 5 and 10 euros per gram (47).
Average prices of cannabis resin, corrected for inflation (48), fell over the period 1999–2004 in all reporting countries (49) except Germany and Spain, where prices remained stable, and Luxembourg, where a slight increase occurred. Average prices of herbal cannabis, corrected for inflation (50), of type unspecified or imported, also decreased over the same period in most of the reporting countries, but remained stable in Spain and the Netherlands and increased in Germany, Latvia, Luxembourg and Portugal. Only two countries, the Netherlands and the United Kingdom, have reported on the average price of locally produced herbal cannabis, and in both cases it has declined.
The potency of cannabis products is determined by their content of Δ9-tetrahydrocannabinol (THC), the primary active constituent (EMCDDA, 2004b). In 2004, the reported average THC content of cannabis resin at retail level varied from less than 1 % (Bulgaria) to 16.9 % (the Netherlands), while herbal cannabis potency ranged from 0.6 % (Poland) to 12.7 % (England and Wales) (51). The potency of locally produced herbal cannabis was reported at 17.7 % in the Netherlands (52).
Cannabis use in the general or school population is assessed through surveys, which provide estimates of the proportion of people that declare having used drugs over defined periods of time: lifetime, last year or last month.
The EMCDDA, in association with national experts, has developed a set of common core items (the ‘European Model Questionnaire’, EMQ) for use in adult surveys, and this has been implemented in most EU Member States. Details of the EMQ are included in 'Handbook for surveys about drug use among the general population' (http://www.emcdda.europa.eu/?nnodeid=1380). However, there are still differences between countries in methodology and year of data collection, and small differences between countries should be interpreted with caution (1).
‘Lifetime use’ is of limited value in assessing current drug use among adults (although it is considered to be a reasonable indicator among schoolchildren), but it can provide insight into patterns of use. ‘Last year use’ and ‘last month use’ reflect the current situation more accurately, with the latter weighted more heavily towards people who use the drug frequently.
The European School Survey Project on Alcohol and Other Drugs (ESPAD) is an important source of information on drug and alcohol use among European school students and is invaluable for recording trends over time. ESPAD surveys were conducted in 1995, 1999 and 2003. The next survey will take place in 2007.
ESPAD uses standardised methods and instruments among nationally representative samples of school students aged 15–16 years, to allow comparability of results. Participation in ESPAD has grown with each survey, with 26 European countries participating in 1995, 30 in 1999 and 35 in 2003, including 22 EU Member States and four candidate countries (Bulgaria, Croatia, Romania and Turkey). The survey questions focus on alcohol consumption and use of illicit drugs, with the standard timeframes, and frequency of use.
Information on ESPAD and the availability of reports can be found on the ESPAD website (www.espad.org).
(1) For more information about methodology of population surveys and the methodology used in each national survey, see the 2006 statistical bulletin.
Cannabis is the illegal substance most frequently used in Europe. Its use increased in almost all EU countries during the 1990s, in particular among young people, including school students.
It is estimated that about 65 million European adults, that is about 20 % of those aged 15–64, have tried the substance at least once (53), although it should be remembered that most of these will not be using the substance at the present time. National figures vary widely, ranging from 2 % to 31 %, with the lowest figures in Malta, Bulgaria and Romania, and the highest in Denmark (31 %), Spain (29 %), France (26 %) and the United Kingdom (30 %) (54). Of the 25 countries for which information is available, 13 presented lifetime prevalence rates in the range 10–20 % (55).
Last year use is clearly lower than lifetime experience. It is estimated that about 22.5 million European adults have used cannabis in the last year, about 7 % of those aged 15–64. National figures range between 1 % and 11 %, with the lowest figures reported by Greece, Malta and Bulgaria, and the highest by Spain (11.3 %), France (9.8 %) and the United Kingdom (9.7 %) (56).
Estimates of last month prevalence will more closely represent regular use of the drug. It is estimated that 12 million European adults have used the drug in the last 30 days, about 4 % of adults. Country figures range between 0.5 % and 7.5 %, a 15-fold difference. The lowest figures were reported from Lithuania, Malta, Sweden and Bulgaria, and the highest from the Czech Republic (4.8 %), Spain (7.6 %) and the United Kingdom (5.6 %) (57).
Use of illegal drugs, including cannabis, is concentrated mainly among young people. In 2004, between 3 % and 44 % of Europeans aged 15–34 reported having tried cannabis, 3–20 % had used it in the last year, and 1.5–13 % had used it in the last month, with the highest figures again coming from the Czech Republic, Spain and the United Kingdom. The European averages for this age group are 32 % for lifetime use, 14 % for last year use (compared with 2 % for 35- to 64-year-olds) and over 7 % for last month use (compared with 1 % for 35- to 64-year-olds) (58).
Cannabis use is even higher among 15- to 24-year-olds, with lifetime prevalence ranging between 3 % and 44 % (most countries report figures in the range 20–40 %), last year use ranging from 4 % to 28 % (in most countries 10–25 %) (Figure 2) and last month use ranging from 1 % to 15 % (in most countries 5–12 %), with higher rates among males than females. In the new Member States levels of cannabis use among young adults aged 15–24 are typically in the same range as those in the EU-15 Member States, but among older age groups rates of use drop substantially (59).
By contrast, in the 2004 US national survey on drug use and health (60), 40.2 % of adults (defined as aged 12 years and older) reported lifetime use, compared with the EU average of about 20 %. This is higher even than in those European countries with the highest lifetime rates (Denmark 31.3 % and the United Kingdom 29.7 %) although differences in last year use estimates are less marked: this figure is 10.6 % in the United States compared with a European average of 7 %, and several European countries reported figures similar to those found in the United States.
Reitox national reports (2005), taken from population surveys, reports or scientific articles.
Five EU Member States (Belgium, Spain, Italy, Cyprus and the United Kingdom) reported new data from national school surveys, and Bulgaria reported data from school surveys conducted in two major cities. Overall, the picture of cannabis use among school students in Europe remains unchanged. The highest lifetime prevalence of cannabis use among 15- and 16-year-old school students is in the Czech Republic and Spain (44 % and 41 % respectively). Countries where the rate is higher than 25 % include Germany, Italy, the Netherlands, Slovenia and Slovakia (27–28 %) and Belgium, France, Ireland and the United Kingdom, where lifetime prevalence ranges from 32 % to 40 %. The lowest lifetime prevalence estimates (less than 10 %) occur in Greece, Cyprus, Sweden, Romania, Turkey and Norway (61).
Prevalence estimates for 15- to 16-year-old students should not be generalised to older students because large increases in prevalence may occur with small increases in age. Among 17- and 18-year-olds lifetime prevalence estimates reach over 50 % in the Czech Republic, Spain and France (62). And in Sweden, where prevalence is low compared with many other Member States, estimated lifetime use of cannabis among 17- and 18-year-old students, at 14 %, is more than double that among 15- to 16-year-olds (6 %) (63).
Cannabis use tends to be occasional or discontinued some time after its initiation. On average, 33 % of Europeans who have ever tried cannabis have also used it in the last year, whereas only 16 % have used it in the last 30 days. These proportions, known as ‘continuation rates’, vary across countries, ranging from 20 % to 45 % for last year continuation and from 10 % to 25 % for last 30 days continuation (64).
In recent years there has been a surge in the level of concern about potential social and health outcomes of cannabis use. Although the available evidence does not provide a clear-cut understanding of the issues, some conclusions may be drawn. It is, for instance, evident that intensive cannabis use is correlated with mental illness, but the question of co-morbidity is intertwined with the questions of cause and effect. The complexities of this correlation are explored and discussed in a forthcoming EMCDDA monograph.
The fact that intensive cannabis use often co-occurs with non-drug-specific mental problems has practical implications. When forming a treatment plan for cannabis users it may be difficult for clinicians to know whether to start with the drug use or the mental health problem. Studies of the effects of treatment for problem cannabis use are still scarce, and the few that exist cover only specific psychosocial treatments. All other treatment modalities have either not been studied at all or insufficiently studied; thus evidence for efficacy and effectiveness is lacking.
Although cannabis use is largely concentrated among young people, there is some suggestion from data from Spain and the United Kingdom that people may be continuing to use the drug into their 30s or 40s. This could represent an important long-term change in cannabis use patterns that merits further attention.
Use of cannabis, like that of other illegal drugs, is notably higher among males than among females. The difference is more marked in the case of last year or last month use than it is for lifetime use, but the differences are smaller among young people than among older adults (see the selected issue on gender). Cannabis use is also more common in urban areas or areas with a high population density. It has been hypothesised that use may be spreading to smaller towns or rural areas, and Poland documented this trend in its 2005 national report.
Despite increasing concerns about regular or intensive forms of cannabis use (65), there is very limited information at European level. A crude estimate drawn in the 2004 annual report (EMCDDA, 2004a) suggests that 1 % of European adults, about 3 million people, could be daily or almost daily cannabis users. Several countries reported increases in regular or intensive cannabis use, but only Spain reported similar data on daily use, with an increase between 1997–99 (0.7–0.8 % of adults) and 2001 (1.5 %), followed by stabilisation in 2003 (1.5 %). It would be valuable to have information from other countries and by specific age groups (e.g. 15–24 years). The French 2003 ESCAPAD study found that 14 % of 17- to 18-year-olds (9 % of girls and 18 % of boys) could be considered to be at risk of problem use, according to a specific scale (CAST). Other countries are also working on scales to assess intensive forms of cannabis use (Germany, Netherlands, Poland and Portugal), and the EMCDDA is promoting collaboration in this area.
Tracking long-term trends in drug use in Europe is made difficult by the absence of reliable time-series data. However, an increasing number of countries have launched surveys from the early 1990s onwards, and some of these are now beginning to provide valuable insights into trends over time.
It is generally considered that cannabis use started to spread in some European countries in the 1960s and became popular in the 1970s and 1980s. Recent national surveys show significant lifetime experience among 45- to 54-year-olds in Denmark, Germany, Spain, France, the Netherlands, Sweden and the United Kingdom, suggesting significant cannabis initiation during the late 1960s and 1970s. An analysis of initiation to cannabis use found a marked expansion of use in Spain during the 1970s, in Germany (West) during the 1980s and in Greece during the 1990s (66). Swedish data document a relatively high level of experimentation in the 1970s among conscripts (15–20 %).
National or local household, conscript and school surveys have shown that cannabis use increased markedly during the 1990s in almost all EU countries, particularly among young people. This increase has continued until recently in almost all countries, although there are signs of stabilisation or even decreases in some cases.
In the United Kingdom, recent cannabis use among young adults (aged 15–34) was the highest in Europe in the early 1990s but slowly declined from 1998 to 2004/05 (67), while in Spain and France rates have recently (2002 or 2003) reached those in found in the United Kingdom (Figure 3). Similar high prevalence levels are also reported for the Czech Republic.
Levels of use are lower in Denmark, Germany, Estonia, Italy, the Netherlands and Slovakia, but all these countries have reported increases in last year use among young adults, as has Hungary, although to a lesser extent. It should be noted that the Danish (2000) and Dutch (2001) data are now relatively old and the current situation is therefore less clear.
In Finland and Sweden prevalence rates are relatively low but also appear to be increasing; however, the difference observed in Sweden between 2000 (1.3 %) and 2004 (5.3 %) is difficult to interpret because of methodological changes (68).
Estimates of last month prevalence also generally increased in the past decade, although pronounced increases occurred only in Belgium and Spain. The United Kingdom has recently reported a decrease in last month use, having previously presented the highest levels in Europe since the early 1990s. In addition, Slovakia reported a decrease between 2002 and 2004. In the Czech Republic and France it was not possible to assess the trend.
In addition, school surveys can give valuable information about trends in drug use among the younger members of the population, which may predict future trends among young adults. In most countries, since 1995, there has been an overall increase in the number of school students who have ever tried cannabis. However, geographical variations in trends are marked. Trends in lifetime prevalence of cannabis use among school students aged 15–16 years can be categorised into three geographical groups. In Ireland and the United Kingdom, which have long histories of cannabis use, lifetime prevalence is high but has remained stable during the last decade (around 37–39 %). In the Eastern and Central European Member States, together with Denmark, Spain, France, Italy and Portugal, lifetime prevalence of cannabis use in 2003 was substantially higher than it was in 1995. In the third group of Member States (Finland and Sweden in the north and Greece, Cyprus and Malta in the south) plus Norway, estimates of lifetime prevalence among school students have remained at relatively low levels (around 10 % and below) (69).
Among the total of approximately 380 000 treatment demands reported in 2004 (data from 19 countries available), cannabis was the primary reason for referral to treatment in about 15 % of all cases, making it the next most commonly reported drug after heroin (71).
Overall, cannabis is also the second most frequently cited drug in reports on those entering treatment for the first time, representing 27 % of new clients reported in 2004, although there are considerable variations between countries with cannabis being cited by only less than 5 % of new clients in Lithuania, Malta and Romania but by more than 40 % of new clients in Denmark, Germany, Hungary and Finland (72). Over the period 1999–2004, the proportion of all new clients seeking treatment for cannabis increased in most countries that reported data (73).
In almost all countries for which data are available, the proportion of new clients reported as seeking treatment for cannabis use is higher than the proportion of all clients; in a few countries the proportions are roughly equal (74). The greatest demand for treatment for cannabis use is in outpatient settings (75).
A number of factors are likely to be associated with the increased demand for cannabis treatment, and this remains an area requiring research scrutiny. Possible reasons for an increase include an escalation in intensive cannabis use and related problems in the population, an increased perception of the risks of cannabis use, an increase in the number of referrals to treatment from the criminal justice system, clearly important in some countries, and changes in the reporting system and/or its coverage (76).
Overall, cannabis clients can be divided into three groups: those who use it occasionally (34 %), those using it once to several times a week (32 %) and those using it daily (34 %). There are marked differences between countries in the frequency of cannabis use among new clients, with the highest proportion of daily cannabis users being reported in the Netherlands and Denmark and the highest proportions of occasional users or those who have not used cannabis in the month prior to treatment being found in Germany, Greece and Hungary. This variation probably reflects differences in referral to treatment (e.g. more referrals from the criminal justice system or from social networks) (77).
The extent to which cannabis users in treatment meet diagnostic criteria for either dependence or harmful drug use is an important question. Currently, this is an area requiring further investigation. As referral practices differ between countries, there is a need for studies to document the differing clinical characteristics of those receiving treatment for cannabis use.
Some clients seek treatment for cannabis use in combination with other drug or alcohol problems, and sometimes the request for treatment is related to more general problems, such as conduct disorder among young people. Furthermore, some recent studies also report that there has been an increase in adolescents seeking treatment for cannabis use who have coexisting mental health problems, and that this may be an important factor influencing demand for treatment (78).
It also important to understand better the needs of cannabis users at the population level. The EMCDDA estimates there are around 3 million intensive cannabis users (defined as daily or almost daily cannabis use) in the EU. Although the number of these requiring interventions is unknown, the number of cannabis-related treatment demands is small in relation to this figure.
The available data suggests that cannabis clients in outpatient treatment centres tend to be relatively young; virtually all cannabis clients new to treatment are under 30 years old. Teenagers in specialised drug treatment are more likely to be recorded as having a primary cannabis problem than are clients in other age groups, with cannabis accounting for 75 % of treatment demands among those younger than 15 years and 63 % among those aged 15–19 years (79).
Most clients report having first used cannabis when in the youngest age groups, with 36.8 % using the drug for the first time before the age of 15. Almost no one seeking treatment reports having used cannabis for the first time after the age of 29 years (80).
Well-implemented universal prevention programmes can delay or reduce the initiation of young people into the use of substances such as tobacco, alcohol and cannabis. The importance of this is underlined by evidence that early-onset users (pre- to mid-adolescence) have a significantly higher risk of developing drug problems, including dependence (Von Sydow et al., 2002; Chen et al., 2005). An additional consideration in striving to prevent or delay the onset of initiation into cannabis use is the fact that adolescents are more vulnerable to cannabis toxicity.
The profiles of young cannabis users, at least in the early stages of consumption, do not differ from those of young alcohol or tobacco users. This supports the idea that universal prevention for young people should not focus on cannabis alone, but should be aimed at preventing use of alcohol and tobacco too.
Gender is an important issue in cannabis prevention (see the selected issue on gender). Boys are at more risk of progression to more intensive use, perhaps because girls are more responsive to parental disapproval and are more cautious in the selection of their peers. However, this is changing as the traditional roles of males and females change in modern societies. In several European countries projects aimed at preventing cannabis as well as alcohol use (Bagmaendene, Denmark; Beer-Group, Germany; and Risflecting, Austria) attempt to address boys’ lack of communication skills. It is known that one reason for intensive consumption of alcohol and cannabis among boys is that they find it difficult to approach girls, and thus these projects offer training in flirting.
Selective prevention in schools targets risk factors associated with drug use such as early school leaving, antisocial behaviour, academic underachievement, low bonding, and infrequent attendance at school and impaired learning because of drug use.
The German project Stoned at School aims to train teachers in early detection and early intervention, prevention of cannabis consumption, and establishing contact between schools and drug counselling facilities. Like similar projects in Austria, it is a 10-module training scheme to increase teachers’ awareness of cannabis consumption and identify pupils at risk.
Brief intervention is an approach that aims to make people reflect on their use of drugs and to provide them with skills to control it. The concept is largely based on motivational interviewing, a non-judgemental, non-confrontational approach that explores the client’s values, objectives, self-assessment of use and gives feedback on discrepancies between the client’s self-image and actual status.
Brief intervention is often targeted at an early stage of a person’s alcohol or drug use to prevent the development of serious drug problems later on. There is evidence for the effectiveness of brief intervention in preventing alcohol and tobacco misuse, and there is growing interest in the value of this approach for other substances.
Brief intervention has been found to be very useful in selective prevention measures targeted at cannabis users who would not normally come into contact with treatment settings. In the case of intensive cannabis users, education-based programmes that emphasise abstinence may not be effective.
Brief interventions are cost-effective and may be particularly appropriate to cannabis users, as they are found to work well with drug users who:
• are experiencing few problems with their drug use
• have low levels of dependence
• have a short history of drug use
• have stable backgrounds (social, academic, family)
• are unsure or ambivalent about changing their drug use.
This kind of approach is now used in several countries, including Germany, the Netherlands, Austria and the United Kingdom, where interventions may take the form of counselling, ‘cannabis courses’ or even self-help websites. For example, the German website-based counselling programme Quit the Shit (www.drugcom.de) is an innovative approach, using telematics, for cannabis users who want to reduce or stop their drug use. Similar websites with self-help components include www.jellinek.nl/zelfhulp/cannabis/frameset.html by Jellinek (the Netherlands) and www.knowcannabis.org.uk/ by HIT (United Kingdom).
Specific drug counselling centres are frequent in Germany, France and the Netherlands. Since January 2005, more than 250 ‘cannabis consultation’ clinics have been set up throughout the French territories. Aimed at teenagers who are experiencing difficulties as a result of their use of cannabis or other drugs, as well as their parents, these facilities are anonymous, free and open to all. They are located in the major French cities for easy access. Consultations are carried out by professionals trained in the use of evaluation tools and brief interventions that deal with addictions, and are also able to identify social, medical or psychiatric services appropriate for clients needing specialised care. This new type of structure is to be subjected a follow-up study. The first available data from the first 2 or 3 months of operation show attendance figures of 3 500–4 000 individuals per month, of whom 2 000–2 500 were cannabis users (the others being parents, relatives and youth workers). Alternative strategies are to offer short but structured courses with around 10 group sessions (Denmark, Germany, the Netherlands, Austria). An accompanying manual, SKOLL (self-control training), has been launched by a Dutch-German EUREGIO project.
Often, cannabis-specific ‘training courses’ rely on the fact that cannabis use or possession is illegal and participants are referred via the criminal justice system. Motivation to participate largely comes from the fact that attendance at such courses is an obligatory part of a judicial sentence. Nonetheless, these methods enable contact with at least part of the group at risk to be established.
Many European selective prevention interventions tend towards the provision of information on cannabis. Several more evidence-based approaches, including normative restructuring (e.g. learning that most peers disapprove of use), assertiveness training, motivation and goal-setting, as well as myth correction (on value associations with cannabis), have yet to become established as standard elements of cannabis prevention programmes. A recent meta-analysis of prevention programmes for vulnerable young people (Roe and Becker, 2005) found that information-based approaches have little or no impact on consumption behaviours or attitudes, whether in universal prevention or selective prevention. The same authors found that comprehensive social influence programmes have an important effect on vulnerable young people.
An important point emerging from the few available evaluations of European selective cannabis prevention projects (FRED, Way-Out, Sports for Immigrants and others; see above and EDDRA at http://eddra.emcdda.europa.eu) is the efficacy of comprehensive social influence techniques. Among the positive effects achieved by these techniques are a reduction in consumption levels, an increase in the self-perception of problem use, a reduction in the main risk factors and associated problems, as well as increased self-control and motivation.
(40) This should be checked against missing 2004 data when available. Data on both number of cannabis seizures and quantities of cannabis seized in 2004 were not available for Ireland and the United Kingdom; data on number of cannabis seizures were not available for the Netherlands in 2004. For estimating purposes, 2004 missing data were replaced by 2003 data. Data on quantities seized in 2004 provided by the Netherlands were only estimates, which could not be included in the analysis of trends to 2004.
(43) See footnote (40). Data on number of herbal cannabis seizures in 2004 were not available for Poland.
(46) See footnote (40).
(48) Taking 1999 as the base year for the value of money in all countries.
(49) Over the period 1999–2004, data on cannabis resin/herb prices were available for at least three consecutive years in Belgium, the Czech Republic, Germany, Spain, France, Ireland, Cyprus, Latvia, Lithuania, Luxembourg, the Netherlands, Poland, Portugal, Slovenia, Sweden, the United Kingdom, Bulgaria (herb only), Romania, Turkey and Norway. However, trends in the Czech Republic were not analysed due to methodological limitations affecting the data submitted.
(50) Taking 1999 as the base year for the value of money in all countries.
(53) The average proportion was computed as the average of national prevalence rates weighted according to the population of the relevant age group in each country. Total numbers were computed by multiplying prevalence among the population concerned in each country and, in countries for which no information was available, imputing the average prevalence. Figures here are probably a minimum, as there could be some underreporting.
(54) In this text, United Kingdom figures are based on the 2005 British Crime Survey (England and Wales), for practical reasons. There are additional estimates for Scotland, Northern Ireland and a combined estimate for the United Kingdom is available (presented in the statistical bulletin).
(60) Source: SAMHSA, Office of Applied Studies, 2004 National Survey on Drug Use and Health (http://oas.samhsa.gov/nsduh.htm#nsduhinfo). Note that the age range for ‘all adults’ in the US survey (12 years and over) is wider than the age standard range for European surveys (15–64).
(62) ESCAPAD youth survey including 17- to 18-year-olds not attending school.
(65) There is as yet no universally accepted definition of ‘intensive cannabis use’; rather the definition varies across different studies. It is, however, a broad term meaning use of cannabis that exceeds a certain threshold of frequency. It does not necessarily imply the existence of ‘dependence/abuse’ or other problems, but it is considered to increase the risk of negative consequences, including dependence. In this chapter, figures refer to ‘daily or almost daily use’ (defined as use on 20 or more days out of the last 30 days). This benchmark has often been used in studies and can be derived from the European model questionnaire. Risk of dependency among less frequent users is lower.
(66) See Figure 4 in the 2004 annual report.
(67) Since 1994, the first year with information based on the British Crime Survey for England and Wales.
(70) The analysis of the general distribution and the trends is based on the data on clients demanding treatment in all treatment centres; the analysis of the profile of clients and the patterns of drug use is based on the data from outpatient treatment centres. A specific analysis on gender breakdown can be found in the selected issue on gender published with the 2006 EMCDDA annual report.
(76) An EMCDDA monograph on cannabis will be published in 2007; three chapters of the monograph will target the issue of the increase in cannabis treatment demand.