Pompidou Group Co-operation Group to Combat Drug Abuse and Illicit Trafficking in Drugs Strasbourg, 2 October 2003 P-PG/MINCONF TECH (2003) 2 POMPIDOU GROUP MINISTERIAL CONFERENCE Dublin, 16-17 October 2003 Technical File Patterns of poly-drug use in Europe An overview of the policy issues arising from the concurrent use psychoactive substances. by Deborah Olszewski & Paul Griffiths, EMCDDA, Lisbon Discussion paper This paper is drafted under the sole responsibility of its author. Its purpose is to stimulate the debate and does not represent in any way an agreed position of the Pompidou Group
P-PG/MINCONF TECH (2003) 2 2 Introduction Much of the debate on the drug problem is substance specific. This might be considered strange, as anyone who has worked closely with those with drug problems will acknowledge that rarely do individuals restrict their appetites to a single substance. The concurrent use of psychoactive substances not only poses problems for the individuals who consume them but also greatly complicates the monitoring and surveillance of drug use and the development of effective interventions and treatments. Increasingly this complexity is recognised and the importance of polydrug use is noted. This term is used, however, to cover a broad spectrum of behaviours and, depending on the definition adopted, a number of distinct issues for drug policies are raised. In this paper a summary is provided of some of the complexities that arise for drug policies from poly-drug use based on an analysis of the European drug situation. This paper develops themes covered in the EMCDDA report of 2002, where polydrug use is included as a special topic issue. Definitional issues No simple definition is available for what constitutes poly-drug use, nor is the term used in any consistent way. The difficulties of pinning down this concept can be seen in the following definition provided by the United Nations Office on Drugs and Crime (from Demand Reduction - A Glossary of Terms), poly drug use is the use of more than one psychoactive drug either simultaneously or at different times. The term is often used to distinguish persons with a more varied pattern of drug use from those who use one kind of drug exclusively. It usually is associated with the use of several illegal drugs. However, in the research literature it may simply refer to combined use of common legal drugs such as alcohol and tobacco. It is important to carefully define the precise use of this term in research and technical reports on drug abuse in terms of which drugs and drug types are being referred to, whether the use is simultaneous or alternating and whether there is a strongly preferred drug when available. When severely dependent heroin users are unable to maintain their supply of heroin they may resort to the use of other central nervous system depressant drugs, such as alcohol, to minimize the experience of opiate withdrawal. In the DSM-IV, poly-substance dependence refers to the repeated use of at least three groups of (psychoactive) substances (not including caffeine and nicotine) but with no single substance predominating. It can be noted from this definition that a conceptual framework for defining poly-drug use can be thought of as consisting of three inter-related dimensions: substances, temporal perspective (time period and overlap) and inclusion criteria. How these dimensions are defined determines the sub-population of drug users who are considered and the policy issues that become important to address. Therefore a priority task is to develop a classification that allows up to identify the key sub-groups that are of concern and to harmonise our definitions and measures to allow a meaningful dialogue based on the samples, studies and indicators that are available. Thus, the concurrent use of cannabis by methadone maintenance clients, the binge use of illicit drugs and alcohol by young people, and the interaction between opioids and benzodiazapines in drug overdose may all be considered issues of poly-drug use but we need to be able to separate them by developing a conceptual framework that allows us to consider their differing implications for public health policy.
3 P-PG/MINCONF TECH (2003) 2 Below we provide elaborations of the dimensions by which poly-drug use is typically defined and then explore how these influence the policy issues raised, based on some examples of data from the EU. A) Substances. A key distinction here is whether the list is restricted to illicit psychoactive substances or extended to include medicines, alcohol, fashionable high caffeine drinks, or even nicotine. B) Temporal perspective (time period and overlap). Prevalence estimates of drug use will vary considerably according to the time window selected, and whether, in addition to drug use that is simultaneous, drug use that is alternating is considered, as in the example given in the UN definition above, where one drug is substituted for another rather than both used together. C) Inclusion criteria. Some perspectives restrict themselves to considering only those cases where use results in identified problems or dependence; others cases where one drug can be seen as having primacy (see DSM-IV). Making EU comparisons is difficult due to the considerable differences in the working definitions of poly-drug use that are employed. The time frames for poly-drug consumption employed by EU monitoring systems can range from a six hour period, through the last 30 days, or the last year, to lifetime experience. Furthermore, the substances included in poly-drug definitions range from combined use of tobacco and alcohol to combined use of heroin and cocaine. In some studies non-dependent use or use failing to fulfil the criteria for a substance misuse problem is ignored. Thus, it is often very difficult to make comparisons based on data from different sources. Differences of levels of reported poly-drug use in treatment samples, for example, may only represent artefacts related to different reporting practices rather than indicate a real difference in substance consumption. Similarly caution is needed in interpreting trends in data over time to ensure that they do not simply represent changes in reporting practice. Poly-drug use and young people trends and availability Studies of poly-drug use show that there is a hierarchy of drug use patterns, resembling the Russian dolls that each enclose another. A heroin user almost certainly uses or has used one or more stimulant drugs, while a user of ecstasy; amphetamine or cocaine is more than likely to use or have used alcohol, tobacco and cannabis (F.Smit et al 2002, Parker and Eggington, 2002, Calafat 2001, Goddard and Higgens 1999). On this basis a number of estimates of poly-drug use may be drawn from general population surveys in the EU. For example, in data shown in Figure 1 (Recent use (last 12 months) of cannabis, amphetamines and cocaine among young adults (15-34 years old) of EU countries ), if poly-drug use is defined as the use of cannabis and amphetamines during the last 12 months, estimates of poly-drug use are produced from this definition that range from less than 1% in Sweden to over 5% in Ireland among young adults. In Figure 2 (Lifetime prevalence among 15-16 year old students in EU countries )on the other hand, the estimate for poly-drug use is based on a definition of lifetime experience of being drunk together with the lifetime experience of cannabis use. Here estimates for poly-drug use prevalence among 15-16 year old school students range from 8% in Sweden and Portugal to a figure as high as 35% in France and the UK.
P-PG/MINCONF TECH (2003) 2 4 Alternatively, in Figure 3. ( Proportion of clients in treatment using more than one drug) data are presented relating to people in contact with specialist drug treatment services across the EU. Here, most (83%) can be considered poly-drug users if this is defined as those reported by treatment staff as using more than one drug when they present to a specialist service. percent Figure 1. Recent use (last 12 months) of cannabis, amphetamines and cocaine among young adults (15-34 years old) in EU countries 25 20 15 10 5 0 Denmark (2000)... Germany (2000)... Greece (1998) (... Spain (2001) (N... France (2000) (... Ireland (1998) (... Italy (2001) (N=... Netherlands (20... Source: EMCDDA 2002 Cannabis Amphetamines Cocaine Norway (1999) (... Portugal (2001)... Finland (2000) (... Sweden (2000)... UK (E&W) (2001... percetn Figure 2. Lifetime prevalence among 15-16 year old students in EU countries Cannabis Been drunk 100 80 60 40 20 0 Denmark Greece France Ireland Italy Netherlands * Portugal Finland Sweden UK Norway Source: ESPAD 1999
5 P-PG/MINCONF TECH (2003) 2 Figure 3. Proportion of clients in treatment in EU countries using more than one drug Source; EMCDDA 2002 17% 83% Clients using at least one second drug (n=65952) Clients not using a second drug (n=13305) Poly-drug use is associated with an increasing and variable range of drug availability, together with changing attitudes to the acceptability of mixing drugs and alcohol. Numbers of drug seizures are usually considered an indirect indicator of supply and availability (although they reflect a range of other factors such as law enforcement resources, priorities and vulnerability of traffickers to enforcement). Seizures of cannabis, amphetamines, ecstasy, LSD, heroin and cocaine have all increased since the mid-1980s. (EMCDDA 2002) Patterns of poly-drug use Information about the functionality of combining particular drugs is based on descriptions by users of attempts to have, and prolong, pleasurable experiences or avoid negative ones (Boys et al 1999). Poly-drug use has can be seen in this analysis to serve a number of distinct functions: it maximises effects, (for example, by combining alcohol and cannabis at a party or heroin and cocaine in an injection), it balances or controls negative effects (for example, taking benzodiazapines to help cope with difficulty in sleeping or with depressed mood following use of a stimulant drug or smoking cannabis to help deal with opioid withdrawal) it substitutes sought-after effects (for example, substituting a preferred stimulant drug that is not obtainable such as cocaine by an alternative such as amphetamine) The substances that are used depend on local availability, fashion and sometimes, where they include medical drugs prescribed to drug users in treatment, local prescribing practices. This does raise a number of important public health issues. For example, control strategies or prevention programmes designed to reduce the availability or desirability of one drug need to be considered in relation to the likelihood that alternative drugs will be substituted. Different groups exhibit differing patterns of poly-drug use. In Table 1, data are presented illustrating that among young people in night-life settings across the EU alcohol together with cannabis is the most common combination of drugs. This can be contrasted with data from EU specialist drug treatment agencies ( see Figure 4) where the most common combinations reported from these sources are: heroin combined with other opiates or with benzodiazepines; heroin combined with cocaine, cannabis, and stimulants or alcohol; and cocaine used with alcohol or stimulants.
P-PG/MINCONF TECH (2003) 2 6 Table 1. Drug combinations used by recreational drug users in the same night % Source: Calafat et al. (1999). Alcohol and cannabis 50.6 Alcohol and ecstasy 11.9 Alcohol and cannabis and ecstasy 10.4 Cannabis and ecstasy 8.4 Alcohol and cocaine 7.8 Cannabis and ecstasy, alcohol and cocaine 7.8 Cannabis, alcohol and cocaine 2 Figure 4. Common combinations of drugs in EU drug treatment agencies: most problematic drug used together with secondary drug(s) Percent using Secondary Drug 125 100 75 50 25 0 Opiates Cocaine Stimulants Hypnotics Hallucinog ens Volatile Inhalants Cannabis Alcohol Cannabis Hpnotics/ Sedatives Stimulants Cocaine Opiates Note: Percentages may add to more than 100 through use of more than one secondary drug Source: EMCDDA 2002 A typology of poly-drug use has been suggested and developed by researchers from the Trimbos Institute in the Netherlands (Smit et al 2002), which attempts to place as many poly-drug users as possible. Using data from secondary school students, three main types of poly-drug users are identified. These are users who: A combine use of alcohol and tobacco B use cannabis in addition to alcohol and tobacco but do not use ecstasy, amphetamines, heroin or cocaine C use ecstasy, cocaine, amphetamines, or heroin in addition to the above Data presented in this study and supported from elsewhere show that the use of one substance increases the likelihood of the use of another and illustrate how patterns of poly-drug use cluster at different levels, or platforms, of involvement. For example, young people who have used ecstasy are more likely to have tried a range of other drugs than young people who have only used cannabis, tobacco and alcohol.
7 P-PG/MINCONF TECH (2003) 2 This clustering can be seen in detail in the data found in Table 2 and Table 3. In Table 2 data from the Netherlands on the last four week prevalence of drug use among 12-16 year-olds can be seen. In the Netherlands the use of any second substance by school students (12-16 year-olds) was higher by a factor of about two amongst alcohol users compared with the general population. Amongst tobacco users the likelihood of cannabis use was three times higher than in the general population. Among cannabis users the prevalence of cocaine use was almost ten times higher and among ecstasy users the prevalence of cocaine use was as much as 43 times higher than in the general population. Heroin use appeared to coincide mainly with the use of amphetamines and cocaine. A similar pattern is found in the data for an older group (14-18 year-olds) of Spanish students provided in Table 3. Although the actual levels of drug experience are not comparable on account of the differing age groups and the differing time periods (last year and lifetime as opposed to last four weeks) that are considered, a similar relationship between the poly-use of different substances is observable: although only 27% of all students had used cannabis, this figure rose to 58% amongst those who had used tobacco and to 90% amongst those who had used cocaine. Table 2. Four week prevalence among 12-16 year olds in the Netherlands % Source: F. Smit et al 2002 Unconditional alcohol tobacco cannabis ecstasy cocaine amphetamines heroin prevalence % alcohol 49.8-80.0 93.0 93.3 94.0 87.7 83.7 tobacco 25.9 41.6-86.0 85.4 85.4 80.9 73.4 cannabis 7.9 14.7 26.3-76.1 74.5 72.1 55.0 ecstasy 1.2 2.3 4.0 11.8-53.9 49.7 46.2 cocaine 1.1 2.0 3.5 10.1 47.0-52.9 49.8 amphetamines 0.9 1.6 2.9 8.4 37.2 45.4-46.7 heroin 0.3 0.6 0.9 2.3 12.5 15.5 16.9 - Table 3. Relationship of consumption of different substances among Spanish school students (14-18 years) % Source: Delegación del Gobierno para el Plan Nacional sobre drogas. Encuesta sobre drogas a la población escolar 2000.Madrid:Ministerio del Interior, 2002 (note: 12 months prevalence for alcohol and cannabis and lifetime prevalence for tobacco and all other substances) Unconditional prevalence % alcohol tobacco cannabis ecstasy cocaine amphetamines Volatile Substances alcohol 75.2-95.2 97.8 98.1 97.4 98.1 93.2 tobacco 34.4 43.5-73.7 80.5 82.6 80.5 62.1 cannabis 26.8 35.2 58.1-88.7 90.1 86.8 64.0 ecstasy 5.7 7.4 13.3 18.6-52.9 59.6 17.8 cocaine 5.4 7.0 13.1 18.1 50.9-50.4 18.3 amphetamines 4.1 5.3 9.6 13.1 43.1 37.9-19.4 volatile substances 4.1 5.1 7.4 9.7 12.9 13.8 19.6 -
P-PG/MINCONF TECH (2003) 2 8 Frequency of use in any given time period is important, as it is potentially associated directly with the level of problems arising from use. In Figure 5, data from a population survey in Germany illustrate that frequency of use for individual drugs is often not the same across all drugs. The majority of people who took ecstasy in the past year did so less than 10 times, whereas for cannabis the majority who had used it had done so repeatedly (i.e. more than 10 times). The finding is important because it illustrates that a distinction is needed between poly-drug use at different frequencies. A small group of drug users in these data are consuming cocaine and ecstasy in an extremely intensive manner. The public health implications in terms of designing appropriate interventions are likely to be different when addressing the regular cannabis smoker who occasional consumes these other drugs from addressing the regular cannabis smoker who has not yet done so, but may be at elevated risk of future problems. Patterns of intensive poly-consumption may be also be of short duration or linked to a specific social event or location. In Figure 6. a study of young holidaymakers in Ibiza suggests that poly-drug use becomes more prevalent during particular social events, during holiday periods or during particularly social and outgoing phases in life. For these short periods of time risks related to drug use may be especially elevated, suggesting the need for targeted prevention and harm reduction responses. This situation highlights the need to consider the context in which poly-drug use occurs when considering the relevant policy-related issues. Figure 5. Frequency of drug use (per year) among those people who had used cannabis, ecstasy and cocaine during the last 12 months. Former West Germany, 1997 percent 100 75 50 1 to 9 times 10 to 59 times 60 to 199 times 200 or more times 25 0 Cannabis Ecstasy Cocaine EMCDDA 2000
9 P-PG/MINCONF TECH (2003) 2 Figure 6. Comparative frequency of ecstacy use in UK and Ibiza (n=269) percent 75 60 45 30 15 0 UK Ibizia <1 day a week 1 day a week 2-4 days a week >5 days a week Source: Bellis M et al 2000 Poly-drug use the need for a holistic approach A key message to emerge from data on poly-drug use is the suggestion that any drug-specific intervention must be placed in the context of a wider framework of patterns of psychoactive substance use, within which individuals exposure to any substance can vary from non-users, through levels of elevated risk of use, to levels of intensity of use (dose and frequency). The increasingly variable range of drugs available and individuals wiliness to experiment present a complex problem for public health responses. This suggests that a coordinated approach to prevention is required that recognises the interrelated and multi-dimensional problems that poly drug use presents us with. Some countries have launched broad mass-media campaigns to warn against multiple drug use in recreational settings. In other countries health warnings and advice are passed through drug workers or peers and self-help groups. Drug Interactions and risk One direct policy implication of poly-drug use is that the combining different types of drugs may increase the risk of health problems occurring. One example where this is clearly the case is that some combination of substances can be shown to increase the risk of overdose. The combinations of drugs identified in mortality and overdose studies provide indications of risks associated with particular drug combinations. In the EU, around 7,000 to 9 000 acute drug deaths (overdoses) are recorded in each year. Results of toxicological analyses of fatal and non-fatal overdoses associated with illegal drug use suggest that a large majority of drug deaths are associated with the injecting of heroin combined with other drugs. Benzodiazapines, alcohol, methadone and cocaine are the substances most frequently found combined with heroin in toxicology reports on drug related deaths. Studies have suggested that opioid overdose is more common when other drugs, particularly benzodiazapines or alcohol, are present suggesting a causal link. (ONS, 2000a and b; Farrell, 1989; Bennett and Higgins,1999; Strang et al., 1999; Taylor et al, 1996). In Table 4. data from Ireland can be found that illustrate that, in most cases of death attributed to opioids subsequent toxicological analysis identified more than one drug type present.
P-PG/MINCONF TECH (2003) 2 10 Table 4. Number of drugs implicated in 254 deaths related to the use of opiates in Ireland Source EMCDDA 2002 National report Ireland, Byrne Number of drugs Frequency Percentage 0 5 2.0 1 17 6.7 2 53 20.9 3 70 27.6 4 60 23.6 5 36 14.2 6 9 3.5 7 3 1.2 10 1 0.4 Total 254 100 Worries about drug interactions are not restricted to opiate overdose: other areas of concern include interaction between cocaine and alcohol, and on the concurrent use of ecstasy with other stimulants. Recently there has been a rising public health concern about the interrelationship between cannabis smoking and tobacco smoking and about the idea that poly-drug use, such as combining cannabis and alcohol, may be particularly likely to impact on driving ability. Scientifically assessing the risks of poly-drug use is complicated due to the wide range of factors involved. Acute health risks that are associated with combinations of psychotropic substances depend not only on the pharmacological properties and amounts of the substances consumed, but also on a range of characteristics of the individual and on social and environmental factors. It must also be pointed out that when substances are manufactured illicitly they may deliberately or accidentally contain a range of compounds,, the interactions of which with other drugs are often unknown. The Role of Alcohol There is growing evidence on the role of alcohol in increasing the risk of poly-drug use. Three examples are: 1. Whilst it is difficult to overdose on benzodiazapines alone, the combination of a large dose of benzodiazapines and a large dose of alcohol or an opiate drug such as heroin or methadone may be fatal. 2. When ecstasy is used with alcohol, health risks increase because alcohol impairs thermal regulation and increases dehydration. 3. When cocaine is combined with alcohol, the combinations may be more directly toxic to the heart and liver than with cocaine or alcohol alone. Alcohol is often present in cocaine cardiac deaths (Leccese et al 2000, Drugscope 2001) In addition, the use of alcohol combined with stimulant drugs has also increasingly been associated with violent, criminal and aggressive behaviour (Budd, 2003, Maguire and Nettleton, 2003) As many drug injectors are infected with hepatitis C, alcohol may be particularly detrimental to them.
11 P-PG/MINCONF TECH (2003) 2 Treatment services for poly-drug users Poly-drug use has been shown to complicate the treatment of those seeking help for drug problems. Drug use treatment is often geared as a response to one particular behaviour, such as heroin use but, as shown in Figure 3, poly-drug users constitute the majority of clients. It should also be noted that those seeking help for drug problems may also have problems related to their alocohol use.. The focus of drug services is often on behaviour rather than substances and the perceived advantage of drug services having regular contact with drug users is considered important. Poly-drug use has implications for the efficacy of treatment. For example, if opiate use is being addressed while co-existing benzodiazapine use is neglected, there is potential for reducing the efficacy of substitution treatment. Again definitional issues complicate any analysis in this area. For example, as discussed earlier most heroin users will also be at least occasional users of other substances. Clarity is therefore needed in comparing data in this area, especially since differences, as reported above, may simply derive from different reporting practice. Further, the extent to which poly-drug use is aproblem will arguably vary according to the intensity of use of the concurrent substances and whether its use results in a diagnosis under one of the accepted diagnostic reporting systems. For an example, a person seeking help for a heroin problem who also drinks alcohol may or may not be diagnosed as a problem drinker. There is considerable debate on the impact of concurrent cannabis use among those receiving heroin substitution treatment, with some commentators arguing that positive outcomes are not influenced and with others contesting this. Clearly poly-drug use is an important issue for drug treatment and yet to date the knowledge base on this area remains insufficient to draw strong conclusions. There is little research on the effectiveness of the treatment of poly-drug users. The UK NTORS study found that, after one year, opiate users who were frequent users of stimulants at intake showed marked improvements in terms of reduced levels of opiate and stimulant use (Gossop et al, 1998). Greece reports that substitution programmes claim that the treatment interventions contribute to a reduction in polydrug use (Kethea NSPH, 2001). The development of special treatment programmes for specific groups such as polydrug users is considered a need by many countries, although currently no clear consensus is evident on what constitutes good practice in this area. Conclusions: Poly-drug use: the need for a clear conceptual framework No short review such as this can hope to list all the issues that are raised by considering the complex nature of the multiple use of psychoactive substances. This review has highlighted some areas that have a clear importance for policies to reduce the negative health and social impact of drug use. The purpose of this exercise has been to provide examples of why it is often not sufficient to restrict our analysis of drug use to single substances. The consequences of poly-drug use are challenging, as it complicates the methods we must use to understand drug use and it complicates the development targeting and evaluation of our measures to address drug problems.
P-PG/MINCONF TECH (2003) 2 12 The central conclusion of this paper is that in order to begin to identify the policy issues that are important when considering poly-drug use, there is a need to first develop a clear conceptual framework that delineates the different areas of interest and concern. Almost all drug users can, under some definition, be considered polydrug users and differences in reporting practice mean that it is often extremely difficult to draw comparisons between different data sources. This is unhelpful, as it reduces the possibility for a policy dialogue to be based on the identification of specific issues, shared reflection on the situation and clear understanding of the scientific evidence. A pressing need therefore is to define the key questions of interest that underlie the broad issue of poly-drug use and to develop some common definitions of the different categories of behaviour that are likely to be of interest. This conceptual framework is likely to be a prerequisite to the development of a sounder understanding of how we more effectively respond to the difficulties with which polydrug use presents us. Currently at European level, EMCDDA is analysing data based on population surveys and treatment attendance to provide a better insight into the prevalence and patterns of poly-drug use in the EU. Such information can help form the basis for considering how to define a typology of poly-drug use in the EU based on measures that are internally comparable. A more general conclusion from the analysis presented here is that data on poly-drug use underlines that individuals drug taking repertoires are both complex and dynamic. Numerous factors influence poly-drug use, including individual rituals, social controls, rationales and beliefs, the context in which drugs are used, the sought-after effects, and the extent to which individuals are dependent or experiencing problems. Environmental factors are also likely to be important and contribute to increased risk among different drug-using groups The complex and ever-changing nature of the drug markets means that holistic prevention strategies are required. Clinicians and drug treatment services need evidence-based knowledge to develop the best possible care for poly-drug users. At present, however, this evidence base remains poorly developed.
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