Diese Schrift war verfasst von G. Edwards and D. Hawks vom "Addiction Research Unit Institute of Psychiatry, University of London, England; herausgegeben wurde sie vom Regional Office for Europe WHO, Copenhagen, 1973.

Diese Schrift beinhaltet keine veränderten Definitionen oder ähnliches, was den "Sucht/Abhängigkeits-Begriff" angeht. Sie wird hier zitiert, weil in ihr ausgiebig definitorische und methodologische Grundfragen erörtert werden. Daraus liessen sich Kriterien für die Bewertung von Studien, aber auch von "politischen Massnahmen" etc. ableiten. Die seinerzeit geforderte Exaktheit bei der Durchführung wissenschaftlicher Arbeiten etc. wird, so der Eindruck des Autors, heute von manchen nicht mehr als tragendes Element der eigenen Arbeit angesehen. Originaltext 1973:

"The necessary characteristics of useful data

Data which can serve the planners, purpose have certain special characteristics, which may be listed as follows:

(1) The data must be credible. The fact that research is being asked to contribute to the planning and decision-making activities of the non-academic world does not mean that any lowering of scientific standards is possible.

(2) The explicative is more useful than the descriptive. Data which have been gathered within a framework of well-thought-out hypotheses, theoretically derived, are likely to be of much greater use than the piles of computer printout which are so easily produced by the uneconomical and unfocused study which comprises quantities of unrelated questions asked for an uncertain purpose.

(3) Data are most useful when they have a time dimension. Preventive action is concerned with the effort to change patterns of drug misuse by a community over a period of time, and therapy is concerned with the effort to change the individual's drug use and social adjustment over a period of time. In the particular area of drug studies, it may seldom be possible to set up the sort of controlled trial which would best serve the purposes of scientific investigation, although such should certainly be the ideal aim. For this reason, and in practice, it may only be possible to assess the impact of some change, for instance, in legal controls, or some large change in treatment policies, by 'before' and 'after' measurement, which is made against some knowledge of the likely extrapolation of change in patterns of drug use had there been no such change in national response.

(4) Any one investigation is more useful when it can be seen in the context of other work, whether in the same or in other countries. There is therefore a practical need for definitions, on which comparative studies can be based.

(5) To the planner who is faced with an immediate problem, information is of most use if it can be obtained quickly. Research teams may sometimes need to focus and divert resources, in a manner not in line with usual academic tradition.

(6) Data which serve the planners' purpose must avoid the overcomplex. Results phrased for instance in complex statistically-derived personality profiles as determinants of outcome, may be of the very greatest long-term interest in personality research, but are of little practical application in normal life.

(7) Data are more likely to serve and illuminate the needs of decision-making when research worker and decision-maker enjoy a continuing dialogue from the earliest stage of research planning to the late stages of reporting and implementation.

2.3 Relevance of data to response - continuous exploration

The general notion that all elements of national response should be rationally rooted is so obvious as to be almost banal and yet there is at present little experience of the practical possibility of making such complex action data-based. There has seldom been the necessary useful data available to give to the policy maker, and he has therefore very understandably acquired the habit of supposing that policies on drug matters must usually be based on intuition rather than on hard data. There must be few recorded instances of partnership between legislature and research investigator, with the efficacy of control measures adequately and objectively assessed. There are probably very few instances where the assessment of any treatmentprogramme's efficacy has led to the abandonment of that programme. The concept of a more rationally informed national response should not, however, be inflated into the idea of some computerized master plan what is needed is a series of experiments in which the possibilities of linking data and action are objectively and practically explored. Action will to some extent always be dictated by political constraints, and research information in such a variable field is always to some extent beset by difficulties of interpretation which it is well to admit. The purpose of apt and thoughtful data collection as put forward in this paper, includes therefore the idea that not only is data collection itself a matter for much thought and study, but also the relationship between the data collected and the action which it, might be thought to illuminate, is a matter for important and continuing investigation."

Es wird die vom "WHO Expert Committee on Drug Dependence" 1969 vorgestellte und vielfach genutzte Definition zitiert:

'Drug dependence was defined by a WHO Expert Committee on Drug Dependence (1969) as 'a state, psychic and sometimes also physical, resulting from the interaction between a living organism and a drug, characterized by behavioural and other responses that always include a compulsion to take the drug on a continuous or periodic basis in order to experience its psychic effects, and sometimes to avoid discomfort of its absence. Tolerance may or may not be present. A person may be dependent on more than one drug.' The report of a WHO Scientific Group on the Evaluation of Dependence-Producing Drugs (1969) points out that 'The characteristics of drug dependence show wide variations from one generic type to another, which makes it mandatory to establish clearly the pattern for each type.' Alcohol is included among the generic types for which 'the consistency of the pattern of pharmaco-dynamic actions is sufficiently uniform to permit at this time accurate delineation'."

In diesem Bericht, der Situationen in 33 Ländern beschreibt, wird auch auf Tabakkonsum eingegangen (Kapitel 14). Nicht überall, heisst es einleitend, werde Tabak in die Kategorie "abhängig-machend" eingestuft. So habe die WHO bei den Vorschlägen zu nationalen Ermittlungen Tabak als Ergänzung zum Hauptteil der Fragen benannt.

Es wird retrospektiv die Haltung der WHO zu Tabakkonsum beschrieben; so habe das Executive Board auf seiner 47. Sitzung die Sammlung von Daten dazu gefordert. In diesem Zusammenhang wird Tabakkonsum als "Gewohnheit" ("habit") definiert. 1972 sei Tabak - im Bericht "Youth and Drugs" - als "abhängigmachend" beschrieben worden, allerdings "leichte psychotoxische Effekte" verursachend.

Im folgenden werden einzelne nationale Massnahmen/Kampagnen gegen Tabakkonsum beschrieben und deren Wirksamkeit erörtert; grundlegende Passagen im Originaltext:

"14.TOBACCO SMOKING

14.1 Health and dependence problem

Although tobacco is not considered everywhere to fall within a category of dependence producing drugs, some authorities state that the dependence mechanisms are similar to those leading to other problems discussed in this report, and certain national bodies, treatment centres, and research institutions deal with problems of tobacco smoking along with dependence on alcohol and other drugs. The WHO Outline for National Inquiry therefore included, as an annex, a rubric on tobacco smoking and about half the responses gave some information on this subject.

In recent years, WHO has shown considerable concern about the health hazards of tobacco smoking. The Executive Board, at its forty-seventh session, adopted a resolution (World Health Organization, 1971) requesting the Director-General 'to continue to assemble information on the effects of smoking and the results of action taken to reduce the habit', and 'to seek the assistance of the United Nations and the specialized agencies in promoting the social change required and in studying the economic consequences, actual and anticipated, of the change.'

In the meantime, the report of a WHO Study Group on Youth and Drugs (1972) has stated, after listing the dependence-producing drugs already mentioned, that tobacco 'clearly is a dependence-producing substance with a capacity to cause physical harm to the user, and ist use is so widespread as to constitute a public health problem. However, unlike the types of dependence-producing drug just noted, it produces relatively little stimulation or depression of the central nervous system, or disturbances in perception, mood, thinking, behaviour or motor function. Any such psychotoxic effects produced by tobacco, even when it is used in large amounts, are slight compared with those of the types of dependence-producing drugs listed above'."

Es wird, verglichen mit den früheren Darstellungen, eine etwas veränderte Beschreibung der "Abhängigkeit produzierenden Drogen" vorgenommen. Die Änderung liegt in der Erweiterung auf nunmehr neun Stoffgruppen, entstanden durch die Teilung der bisherigen "Alkohol-Barbiturat-Gruppe" in zwei Gruppen (Originaltext am Ende dieses Textes).

Änderungen sind auch bei "Tabak" vorgenommen worden. "Tabak" wird jetzt neben anderen Stoffgruppen aufgeführt; es werden genannt: "Tabak und gewisse Analgetika wie Aspirin und Phenacetin". Diese Stoffe seien "in gewissem Ausmass" geeignet, Suchtabhängigkeit zu erzeugen; in "einigen Fällen" könne es sogar zu einer sehr deutlichen Abhängigkeit kommen.

Die im Text enthaltene Wertung, die Abhängigkeit von "Tabak" und nun auch einigen Analgetika sei eigentlich nicht mit einer Abhängigkeit von einer der genannten neun Stoffgruppen zu vergleichen; Originaltext:

"Comment on tobacco and analgesics

While the term 'dependence-producing drug', as used here, refers to one or more of the 9 types listed above, there are some other types of substance (e.g., tobacco and certain analgesics, such as aspirin and phenacetin) that may clearly give rise to some degree of drug dependence. In some cases, dependence may even be very marked. The intensive use of these substances may result in serious physical harm to the user, and in the case of tobacco, at least, use is so widespread and the associated problems so serious as to constitute a public health problem. However, unlike the dependence-producing substances listed above, tobacco and the analgesics in question produce relatively little stimulation or depression of the central nervous system or disturbances in perception, mood, thought, behaviour, or motor function. Any such psychotoxic effects produced by tobacco and the analgesics, even when large amounts are taken, are slight compared with those of the dependence-producing drugs. Only the use of dependence-producing drugs capable of exerting major psychotoxic effects is dealt with in this manual."

Die nunmehr veränderte Beschreibung der neun Stoffgruppen im Originaltext:

"(1) alcohol type: alcoholic beverages of all kinds

(2) amphetamine type: e.g., amphetamine, dexamphetamine, methamphetamine, methylphenidate, and phenmetrazine;

(3) barbiturate type: e.g., barbiturates (especially those with a short or intermediate duration of action) and certain other drugs with sedative effects, such as chloral hydrate, chlordiazepoxide, diazepam, meprobamate, and methaqualone;

(4) cannabis type: preparations of Cannabis sativa L., including marihuana (bhang, dagga, kif, maconha), ganja, and hashish (charas);

(5) cocaine type: cocaine and coca leaves

(6) hallucinogen (LSD) type: e.g., dimethyltryptamine (DMT), lysergide (LSD), mescaline, peyotl, and psilocybin ;

(7) khat type: preparations of Catha edulis Forsk

(8) opiate (morphine) type : e.g., opium, morphine, heroin, codeine, and synthetic drugs with morphine-like effects, such as methadone and pethidine;

(9) volatile solvent (inhalant) type: e.g., toluene, acetone, gasoline, and carbon tetrachloride, and also certain anaesthetic agents such as ether, chloroform, and nitrous oxide."

Es werden in dieser Quelle die Begrifflichkeiten "Drogenmissbrauch" und "Drogenabhängigkeit" unterschieden. Bezüglich der "Drogenabhängigkeit" wird dargestellt, dass sich mit ihr nach einigen Auffassungen der schwere Schäden für den Abhängigen verbinden müssen; es werden "Verhaltensveränderungen", hervorgerufen durch die Droge ("habit-forming drugs"), als Kriterium genannt.

"Comment on the terms 'drug abuse', 'addiction', and 'habituation'

'Drug abuse' is a term in need of some clarification. A definition acceptable to a majority of persons concerned with the problem-related use of drugs would be difficult to formulate. The term is really a convenient, but not very precise, way of indicating that (1) an unspecified drug is being used in an unspecified manner and amount by some person or persons, and (2) such use has been judged by some person or group to be wrong (illegal or immoral) and/or harmful to the user or society, or both. What might be called 'drug abuse' by some would not necessarily be considered so by others. Further, many drug users, whether experimental, casual, or dependent, and some non-users, also, tend to ignore the views of persons who use this term because, rightly or wrongly, they are seen as prejudiced or poorly informed. For these reasons, the term 'drug abuse' is avoided here.

'Drug addiction' is another term whose various definitions have created substantial problems and misunderstandings. Some authorities would argue that physical dependence must be present for a state of addiction to exist; others would disagree. Nearly all would accept cocaine as an 'addicting' drug since craving for it may be very intense, yet it produces no physical dependence. Further, the term 'addiction' usually carries the connotation of serious harm to the drug-taker and/or society, and implies the need for a particular type of control; these connotations are inappropriate in view of the different types of drug dependence and differences in the degree of dependence liability characterizing different dependence-producing drugs. The term 'habituation' has been used variously to indicate that there is either an absence of physical dependence on the drug in question and/or that the consequences of using a 'habit forming' drug are less serious than those associated with the use of an 'addicting' drug. Attempts to differentiate between 'addiction' and 'habituation' have been of little help since the same two issues (i.e., the nature of the condition and the possible need for control) are combined in a single term."

Das folgende Zitat enthält Hinweise auf z.B. Verhaltensweisen, so die den Menschen innewohnende Neugier ("Curiosity"), soziale Beziehungen, personale Entwicklungen, die - auch temporär - Suchtphänomene hervorrufen könnten; Originaltext:

"No single 'cause' of drug-taking has been demonstrated, but the following motives and hypotheses are among those most frequently put forward to 'explain' why drug-taking is begun or pursued. Persons who take dependence-producing drugs apparently do so for a great variety of stated or unconscious reasons at different times. However, one or more of the following motives often appear to be associated with the initiation and continuation of drug-taking: (1) to satisfy a personal curiosity about drug effects; (2) to achieve a sense of belonging, i.e., to be 'accepted' by others; (3) to express independence and sometimes hostility; (4) to have pleasurable, new, thrilling, or dangerous experiences; (5) to gain an improved 'understanding' or 'creativity'; (6) to foster a sense of ease and relaxation; and (7) to escape from something.

It must be noted that these motives are not necessarily associated with individual psychopathology or with adverse social influences. They can be, and are, operative for normal as well as abnormal persons, whether or not such persons are satisfied with the social structure and the situation in which they find themselves. Furthermore, these motives do not necessarily lead to drug-taking. Indeed, they can and do induce most people to obtain satisfaction through activities other than drug-taking.

Curiosity is one of man's outstanding characteristics; it appears early in life and leads to extensive exploratory behaviour. It is therefore not surprising that many young persons wish to try certain drugs in order to discover their effects for themselves. Since a great many young people first use drugs (especially alcohol and cannabis) in the company of others, the novice may find that, in endeavouring to satisfy his curiosity, he may also have achieved a sense of 'belonging' to the group involved and/or a sense of independent responsibility for his actions. Indeed, the first or subsequent trials may be more related to the experimenter's need for acceptance as a person or a sense of independence than to his curiosity. It is understandable that these powerful factors, reinforced by the pharmacological and other effects of taking dependence-producing drugs, will make such drugs attractive for some persons once they have tried them. Among the possible reinforcing pharmacodynamic properties of various types of dependence-producing drug are: relief from pain, anxiety, fear, inhibitions, and excessive passivity; a sense of ease, relaxation, and blunting of consciousness; a sense of decreased fatigue and heightened awareness of both external and internal sensory and other stimuli, sometimes to an intense degree; a sense of increased understanding, insight, or creativity; and the production of dreamyand/or euphoric states.

A knowledge of the pharmacological interaction between the drug and the drug-taker and of the interaction between the drugtaker and the environment is essential to an understanding of drug dependence. Given that pharmacological, human, and environmental factors are present, some of the many hypotheses put forward to explain the causation of drug dependence include the following :

'(1) that such drug dependence may be a manifestation of an underlying character disorder in which immediate gratification is sought in spite of the possibility of long-term adverse consequences and at the price of immediate surrender of adult responsibilities;

'(2) that it may be a manifestation of delinquent-deviant behaviour in which there is pursuit of personal pleasure in disregard of social convention, so that to some this is primarily a moral problem ;

'(3) that it may be an attempt at self-treatment by persons suffering from (a) psychic distress either of the normal variety seen, for instance, in adolescence or as a reaction to social and/ or economic stress, frustration, or blocked opportunity; or the more persistent problem of depressive illness, chronic anxiety, or other psychiatric disorders; (b) physical distress - hunger, chronic fatigue, or disease; (c) a belief that the drug has special powers to prevent disease or to increase sexual capacity;

'(4) that it may provide a means of achieving social acceptance in a social subculture, particularly for the socially inadequate;

'(5) that it may be a manifestation of a permanent or reversible metabolic lesion brought about by the repeated use of high doses of drugs;

'(6) that it may be part of a rebellion against conventional social values relating to pleasure, tradition, success and status ;

'(7) that, even in the absence of pre-existing psychopathology, it may result from the acquisition of a complex set of instrumental and classically conditioned responses and may therefore be a form of learned behaviour;

'(8) that, even in the absence of underlying psychopathology, it may result from sociocultural pressures leading to heavy use of a drug, for example, alcohol ;

'(9) that any or all of these factors may play a role in the causation of drug dependence in a given individual.'

'It will be noted that, for the most part, these hypotheses are non-specific with respect to drug use; that is, most of these factors may be operative with respect to many types of behaviour other than drug taking. The same is also true of such precipitating factors as '(a) rejection by, or separation from, a person upon whom the individual was emotionally dependent; (b) transition to a more demanding adult role, such as those involving occupational responsibilities, sexual relationships, marriage and parenthood; and (c) serious adverse circumstances or physical illness.'"

(1975, Technical Report Series 577)

In diesem Text werden ebenfalls methodologische Fragen erörtert, auch Erkenntnisfortschritte beschrieben. Es wird dargestellt, welche Techniken und Methoden zur Behandlung der oben genannten Fragen sinnvoll einsetzbar seien, z.B. heisst es:

"4. GENERAL METHODOLOGICAL PRINCIPLES

The most direct way to determine whether or not a particular drug is producing dependence at a certain level is by the epidemiological assessment of known cases of dependence after exposure of a sufficiently large human population to the drug. Since it would be unethical to institute experiments of this sort in man, predictive test procedures are required to evaluate the risk of induction of dependence.

In the initial stages of evaluation the characterization of the general pharmacological profile of a drug may be useful. At later stages, there is a progressively greater need for procedures that measure responses regarded, on the basis of scientific evidence, as being intimately related to the induction of compulsive drug-taking in man.

Production of dependence is not an all-or-none phenomenon. Nevertheless, evaluations and decisions have to be made in research laboratories about the development of drugs and about their control in regulatory agencies on the basis of data from preclinical, clinical, and epidemiological studies.

Many drugs are taken in excessive amounts and on a long-term basis for a variety of reasons. The objective of the techniques of study described here is to identify drugs with such strong reinforcing effects that, primarily because of their pharmacological properties, their consumption leads to dependence and poses a universal risk to public health.

Drugs without dependence-producing potential are sometimes used in excessive quantities. Non-pharmacological factors - such as fashion or behavioural or environmental pathology - or psychopathological states can stimulate and sustain drug-seeking behaviour. Knowledge of the extraneous factors leading to this form of excessive consumption is not extensive enough at this time to permit laboratory replications for testing. Behavioural research in this area is progressing, however.

As in other fields, tests for dependence-producing properties have to be evaluated to their specificity, practicability, reliability, and predictive value. Since all pharmacological tests have some limitations, evaluation of the dependence-producing potential of particular drugs has to be made on the basis of the accumulated evidence from multiple tests. Reliability of tests is increased when multiple measures are taken of a range of responses in the same subject.

Using multiple tests, it is desirable to match the profile of action of new drugs with reference drugs known to be dependence-producing. If the profile of action of a new drug is very similar to that of the appropriate reference drug, the probability that the new drug will also produce dependence is very high.

There are two problems inherent in this research strategy. One problem is the selection of characteristics on which to base the comparison of profiles. For example, as Fraser et al. have pointed out, the profile of action of propoxyphene in dependence tests is very similar to that of morphine, and yet the actual incidence of dependence on propoxyphene is significantly less than that of morphine, the suggestion being made that the low incidence of abuse of propoxyphene results from its side effects and its strong local irritating properties.

The second type of problem is that there are many new drugs whose pharmacological profile is different from that of available reference dependence-producing drugs. Drugs with a new profile of action are less likely to be classified correctly. Therefore, caution must be exercised to avoid errors of classification, especially those of the false negative type."

(Quelle: WHO Expert Committee on Drug Dependence, 28th Report, WHO Technical Report Series 836, WHO, Geneva, 1993)

Das "WHO Expert Committee on Drug Dependence" traf in Genf vom 28. 9. bis 2. 10. 1992 zusammen. Dr. Hu Ching-Li, Assistant Director-General, gab einen Überblick über die Geschichte des Committee und der von diesem veranlassten Terminologie; Originaltext:

"Dr Hu explained that, during the 1960s, the title of the Committee had been changed from the 'WHO Expert Committee on Dependence-Producing Drucs' to the 'WHO Expert Committee on Drug Dependence'. At its thirteenth meeting (2), the Committee had decided to abandon the terms 'drum, addiction' and 'habituation' in favour of 'drug dependence' and its terms of reference had been expanded to include all technical matters related to drug dependence. Subsequently, at its twentieth meeting in 1973 (3), the Committee had discussed a wide range of topics concerning problems related to the non-medical use of psychoactive substances."

Die Erweiterung von Definitionen kann Folge veränderter Konzepte sein. Die WHO hat einen umfassenden Gesundheitsbegriff entwickelt. Neben der körperlichen Gesundheit soll auch soziales Wohlbefinden etc. integraler Bestandteil von "Gesundheit" sein. Die Verwirklichung des umfassenden Gesundheitsbegriffes gilt der WHO als ein erreichbares Ziel; dieses zu erreichen unternimmt sie erhebliche Anstrengungen (Details im Ordner "WHO" auf der CD; in der im Ordner befindlichen Datei "Inhalt" sind die Dokumente einzeln beschrieben).

Möglicherweise ist die Einstufung des Tabaks als ein Abhängigkeit erzeugender Stoff - oder gar die Definition als schlimmster Suchtstoff überhaupt (siehe die Beschreibung 1999, wie sie auf S. 120 zitiert ist) mit politischen Erwägungen verbunden gewesen. Bedauerlicherweise ist die entsprechende Begründung, enthalten in:

"Revised guidelines for the WHO review of dependence-producing psychoactive substances for international control in: Executive Boeard, 88th session, Geneva, 15-24 January 1990; resolutions and decisions; annexes"

nicht veröffentlicht, sondern nur auf Anforderung direkt bei der WHO erhältlich. Diese Quelle war auch nicht via Internet abrufbar.

In der obigen Quelle (WHO Technical Report Series 836) wird als Motiv für die Neubewertung des Tabaks keine pharmakologisch-toxikologische oder sonstige naturwissenschaftliche Begründung gegeben; es wird eine eher aus politischer Verantwortlichkeit geborene veränderte Grundhaltung beschrieben:

"It should be noted that, although the dependence-producing properties and public health problems caused by tobacco were recognized at the time of the twentieth meeting, they were not included in the report since its acute effects on behaviour were minimal. At its present meeting, the Committee felt that the evidence for the dependence-producing properties of nicotine and the severe health consequences of tobacco and other forms of nicotine use warranted their inclusion in its report."

Weiter im Originaltext:

"2. Concepts and definitions

Many of the concepts and terminology used at the time of the twentieth meeting are still valid. However, there have been some subtle shifts in the terminology, reflecting recent research findings and a global sharing of information. The basic focus of the twentieth meeting was 'actions taken in an effort to prevent entirely or reduce the seriousness of the individual and social problems associated with the use of various types of dependence-producing drugs' (3), and this focus was adopted by a WHO Expert Committee on Problems Related to Alcohol Consumption (4). At its present meeting, the Committee also adopted this broad frame, addressing a variety of problems related to the harmful use of psychoactive substances. In the International Statistical Classification of Diseases and Related Health Problems (ICD-10), Tenthh Revision (5), 'harmful use' is defined as 'a pattern of psychoactive substance use that is causing damage to health ... physical or mental'. The Committee's main concern was to identify ways of reducing or eliminating the actual or potential harm to health and social functions, resulting from use of psychoactive drugs. For clarity, the term 'drug-related problem' has sometimes been used to refer to a specific type of harm.

Although there have been subtle shifts in the definition of 'dependence' since the twentieth meeting, drug dependence remains the primary concern of the Committee. A conceptual clarification in recent years, however, has distinguished between the specific problem of dependence and the broad range of problems or disabilities related to drug use, among which dependence is included (6).

At its twentieth meeting, the Committee organized its discussion of the range of strategies for reducing drug-related problems in terms of primary, secondary and tertiary prevention, as defined below. At ist present meeting, the Committee also emphasized the need for integrated policies covering all these strategies, but decided to consider them under the headings of treatment and prevention.

* Primary prevention is aimed at ensuring that a disorder, process or problem will not occur.

* Secondary prevention is aimed at identifying and terminating or modifying for the better a disorder, process or problem at the earliest possible moment.

* Tertiary prevention is aimed at stopping or retarding the progress of a disorder, process or problem and its sequelae even though the basic condition persists.

The Committee considered the different types of drug use and drug-related problems in the population as a whole, including the total range of patterns of use and the associated health risks. It is now well established that the level of consumption of alcohol in a population relates to rates of liver cirrhosis mortality and various other chronic health problems. These findings have encouraged a reconceptualization of alcohol consumption levels in the population as a continuum, with no natural dividing point between heavier and lighter drinking, and have supported the idea that alcohol-related problems - including dependence - are related to alcohol consumption patterns. This idea is now seen as applicable to all psychoactive drugs and implies that, in order to reduce the risk of harm, preventive strategies must be directed not only to those with the highest levels of consumption but also to those with less heavy patterns of use.

In the past decade the concept at the heart of the twentieth meeting, that of 'preventing problems associated with the use of psychoactive dependence-producing drugs', has been put forward by some sectors of the research, prevention and treatment communities as 'harm minimization' or 'harm reduction'. This approach has sometimes been contrasted with a singular focus on reducing drug use per se. Examples of harm reduction strategies include the provision of methadone and needle-exchange programmes for heroin users to reduce the risk of HIV infection, the provision of nicotine patches for tobacco users and attempts to reduce alcohol intoxication or its potential consequences by changing the environment in which people drink.

In the harm minimization approach, attention is directed to the careful scrutiny of all prevention and treatment strategies in terms of their intended and unintended effects on levels of drug-related harm. A concern often expressed about harm reduction strategies is their potential for communicating a message condoning drug use. Such concerns have been expressed, for instance, concerning mass media programmes that encourage drinking, groups to nominate a non-drinking 'designated driver', since this message might seem to condone drunkenness in the other group members, and concerning those that provide information about methods of solvent inhalation that reduce the risk of fatalities and other harm. Often these concerns can be alleviated by targeting the message to those already involved in hazardous drug use. In considering such strategies, it should be kept in mind that the public health sector has always been in favour of preventing or reducing the immediate drug-related harm, even if this involves some risk of a more distant hazard or can be seen as condoning drug use.

Since the twentieth meeting, patterns of repeated use of and dependence on non-psychoactive drugs have also become prominent. Media attention has focused on the use of steroids and other performance enhancers in competitive sports, but such drugs have also become widely used among amateur body-builders. The potential for serious health harm from repeated use has motivated some countries to place steroids under the same regulations as medicinal psychoactive drums. Future years may well see the development and use of new medicinal drugs which enhance other aspects of individual performance, such as intellectual capacity. These developments suggest the need for future consideration of the advisability of expanding the terms of reference of the Committee beyond the scope of psychoactive drugs, to include habitual non-medical use of other drugs, regardless of the motivation for use. The Committee noted that dependence on psychoactive drues may also arise where use is not for subjective pleasure or to relieve distress, as with the use of amfetamines by long-distance lorry-drivers and others to ensure wakefulness. The habitual non-medical use of steroids and other non-psychoactive drugs is covered in ICD-10 under category F55, 'Abuse of non-dependence-producing substances' (5).

Until the 1960s, the Committee used the terms drug abuse, habituation and addiction to describe the various states associated with drug use. Indeed, the term drug abuse is contained in the laws of many countries and in the international conventions. At its present meeting, however, the Committee decided to use the term 'harmful use' rather than 'abuse' (see section 2.2.4). Until the 1960s, the term addiction was widely used to refer to the presence of both psychic and physical dependence, whereas the term habituation was used to describe the presence of psychic dependence on a drug. During the 1960s, the Committee made several attempts to clarify the difference between

these two concepts; however, at its thirteenth meeting, the Committee decided to abandon these terms in favour of the term 'drug dependence' (2).

At its sixteenth meeting, the Committee defined drug dependence as: 'A state, psychic and sometimes also physical, resulting from the interaction between a living organism and a drug, characterized by behavioural and other responses that always include a compulsion to take the drug on a continuous or periodic basis in order to experience its psychic effects, and sometimes to avoid the discomfort of ist absence. Tolerance may or may not be present. A person may be dependent on more than one drug' (7). This definition has been widely accepted and was reaffirmed at the twentieth meeting.

Focusing on the clinical aspects of drug dependence, WHO has developed diagnostic guidelines for the various mental and behavioural disorders due to the use of psychoactive substances. The ICD-10 Classification of mental and Behavioural Disorders, Clinical descriptions and diagnostic guidelines (8) provides a clinical description of dependence syndrome and guidelines for diagnosing this disorder.

The Committee compared the above definition of drug dependence with the clinical description of dependence Syndrome in the ICD-10 diagnostic guidelines (8), and concluded that there were no substantial inconsistencies between the two, since:

- both define a strong desire or a sense of compulsion to take the drug, as manifested by drug-seeking behaviour which is difficult to control, as the essential component of dependence; and

- both consider withdrawal syndromes (or physical dependence) and tolerance merely as consequences of drug exposure which, alone, are not sufficient for a positive diagnosis of drug dependence.

The Committee also noted that the distinction between physical dependence and psychic dependence, as described in the report of the twentieth meeting (3), was difficult to make in clinical situations. Furthermore, the Committee felt that this distinction was not consistent with the modern view that all drug effects on the individual are potentially understandable in biological terms. The Committee also noted that the term physical dependence had been found confusing because clinicians often interpreted the manifestation of withdrawal syndromes as evidence of both physical dependence and drug dependence, as defined at the sixteenth meeting (7).

For these reasons, the Committee was of the opinion that it would be less confusing to follow the ICD-10 diagnostic guidelines (8) in not making a distinction between physical dependence and psychic dependence. Furthermore, it felt that the following definition of drug dependence, which is compatible with that used in the report of the sixteenth meeting (7), would be more readily understood for the purposes of this report:

A cluster of physiological, behavioural and cognitive phenomena of variable intensity, in which the use of a psychoactive drug (or drugs) takes on a high priority. The necessary descriptive characteristics are preoccupation with a desire to obtain and take the drug and persistent drug-seeking behaviour. Determinants and the problematic consequences of drug dependence may be biological, psychological or social, and usually interact.

It should be emphasized that both dependence and harmful use (see section 2.2.4) often interfere with the functioning of the individual in society, but the type and extent of this interference depend upon the social, cultural and religious context.

The Committee recognized the importance of the term physical dependence in pharmacology, but felt that its inclusion in this report might lead to confusion with the general term drug dependence. It therefore decided to use the term 'withdrawal syndrome', described in terms of its relevant consequences as follows:

After the repeated administration of certain dependence-producing drugs, e.c,. opioids, barbiturates and alcohol, abstinence can increase the intensity of drug-seeking behaviour because of the need to avoid or relieve withdrawal discomfort and/or produce physiological changes of sufficient severity to require medical treatment.

The Committee also adopted the following definitions and usages for the purposes of its report.

Tolerance is a reduction in the sensitivity to a drug, following ist repeated administration, in which increased doses are required to produce the same magnitude of effect previously produced by a smaller dose. This increase in dose may be necessitated by changes in the metabolism of the drug, or a cellular, physiological or behavioural adaptation to the effects of the drug.

At its sixteenth meeting, the Committee defined the term drug abuse as 'persistent or sporadic excessive drug use inconsistent with or unrelated to acceptable medical practice' (7). The Committee felt that this term was ambiguous and should be replaced with the term 'harmful use' in this report, except in section 10, where individual psychoactive drugs are discussed in the context of their international control. Since the conventions on which the international control of dependence-producing psychoactive drugs is based use the term 'abuse', the same term is used for the sake of consistency.

Harmful use is defined as a pattern of psychoactive drug use that causes damage to health, either mental or physical. The Committee noted that harmful use of drugs by an individual often has adverse effects on the drug user's family, the community and society in general.

A dependence-producing drug is one that has the capacity to produce dependence, as defined in section 2.2.1. The specific characteristics of dependence will vary with the type of drug involved. The existence of a state of dependence is not necessarily harmful in itself, but it may lead to self-administration of the drug at dosage levels that produce deleterious physical or behavioural changes constituting public health and social problems. ICD-10 recognizes the following psychoactive drugs, or drug classes, the self-administration of which may produce mental and behavioural disorders, including dependence (5):

* Alcohol

* Opioids

* Cannabinoids

* Sedatives or hypnotics

* Cocaine

* Other stimulants, including caffeine

* Hallucinogens

* Tobacco

* Volatile solvents

* Other psychoactive substances, and drugs from different classes used in combination.

It should be noted that, although the dependence-producing properties and public health problems caused by tobacco were recognized at the time of the twentieth meeting, they were not included in the report since its acute effects on behaviour were minimal. At its present meeting, the Committee felt that the evidence for the dependence-producing properties of nicotine and the severe health consequences of tobacco and other forms of nicotine use warranted their inclusion in its report. Furthermore, it recommended that WHO should consider expanding the Committee's terms of reference to include substances such as steroids, which are used not because of their psychoactive properties, but because of their performance-enhancing effects. This form of use is described in ICD-10 under catecory F55, 'Abuse of non-dependence-producing substances' (5). The development of other performance-enhancing drugs may present a new type of drug use problem in the future.

The Committee welcomed the publication of The ICD-10 Classification of Mental and Behavioural Disorders. Clinical descriptions and diagnostic guidelines (8) for general diagnostic use by clinicians. It deals with a wide variety of disorders due to the use of psychoactive drugs, including tobacco, and provides guidelines for the diagnosis of dependence, harmful use, withdrawal syndromes, acute intoxication and other clinical states. The Committee also endorsed, for use in clinical research, The ICD-10 Classification of Mental and Behavioural Disorders. Diagnostic criteria for research (9), which is due to be published at the end of 1993.