Bull. Org. mond. Sante 1965, 32, 721-733 Bull. Wld Hlth Org. Drug Dependence: its Significance and Characteristics NATHAN B. EDDY, M.D.,1 H. HALBACH, Dr. med. Dr.-Ing.,2 HARRIS ISBELL, M.D.3 & MAURICE H. SEEVERS, M.D.4 It has become impossible in practice, and is scientifically unsound, to maintain a single definition for all forms of drug addiction and/or habituation. A feature common to these conditions as well as to drug abuse in general is dependence, psychic or physical or both, of the individual on a chemical agent. Therefore, better understanding should be attained by substitution of the term drug dependence of this or that type, according to the agent or class of agents involved, in discussions of these conditions, especially inter-disciplinary. Short descriptions, followed by concise listings of their characteristics, are formulated for the various types ofdependence on atpresent widely abused major groups ofsubstances. CONTENTS Page Introduction ......... .. .. .. .. 721 The term " drug dependence " . 722 Characteristics of drug dependence . 724 Morphine Type . 724 Barbiturate-Alcohol Type . 725 Cocaine Type . 727 Cannabis (Marihuana) Type . 728 Amphetamine Type . 729 Khat Type . 730 Hallucinogen (LSD) Type ......... 731 Resume. 731 References .................... 733 INTRODUCTION notification from a government, the Committee come Among the functions of the World Health Organ- to a finding as to whether or not the substance in ization is the taking of decisions on the status of question is or is convertible into one with addiction- individual drugs under the relevant international producing or addiction-sustaining properties similar treaties for narcotics control. This function has been to those of morphine or cocaine or cannabis. A posi- established by international conventions and depends tive finding by the Committee is followed by a recom- upon the competence of the WHO Expert Com- mendation for appropriate international narcotics mittee on Addiction-Producing Drugs. The con- control. Pertinent to any conclusion or decision is ventions specifically direct that, in response to a the consideration of specific therapeutic effects, the liability of substances having such effects to 1 Consultant, National Institutes of Health, Bethesda, produce drug dependence, and the evaluation of Md., USA. the risk to public health if such substances are 2 Chief, Pharmacology and Toxicology, World Health used for medical Organization, Geneva, Switzerland. purposes or abused. Obviously, ' Professor of Medicine and Head, Section of Clinical such considerations depend upon the availability Pharmacology, Department of Medicine, University of of dependable methods and critical evaluation of Kentucky, Lexington, Ky., USA. their application to the determination of both useful 'Professor of Pharmacology and Chairman of the Department, The University of Michigan, Ann Arbor, therapeutic properties and the kind and degree of Mich., USA. dependence that may accompany drug use. WHO 1604 -721 722 N. B. EDDY AND OTHERS has already published a series of reports on these individuals will not get a reaction satisfactory or requirements (Braenden, Eddy & Halbach, 1955; pleasurable to them, persuading them to continue Eddy, Halbach & Braenden, 1956, 1957; Halbach its use even to the point of abuse-that is, to exces- & Eddy, 1963; WHO Scientific Group on the sive or persistent use beyond medical need. Probably Evaluation of Dependence-Producing Drugs, 1964). the only exceptions are agents that have incidental As a partial guide to its own deliberations and or side effects that prevent such use-for example, those of others, the WHO Expert Committee on cumulative or early toxic effects, to which the Addiction-Producing Drugs (1952) attempted to individual does not become tolerant. formulate a definition of addiction that would be to applicable drugs under international control. THE TERM " DRUG DEPENDENCE" A revised definition 1 was proposed by the Com- mittee several years later, in its seventh report In order to try to clarify this situation, much (WHO Expert Committee on Addiction-Producing thought and discussion have been devoted to finding Drugs, 1957). a term that will cover all kinds of drug abuse. The In its seventh report the Committee sought also component in common appears to be dependence, to differentiate addiction from habituation and whether psychic or physical or both. Hence, use of wrote a definition of the latter 2 which, however, the term " drug dependence " with a modifying failed in practice to make a clear distinction. These phrase linking it to a particular type of drug in order definitions gained some acceptance, but confusion to differentiate the characteristics associated with in the use of the terms addiction and habituation, one class of drugs or another has been given most and particularly misuse of the former, continue. careful consideration. In its thirteenth report, the Both terms are frequently used interchangeably and WHO Expert Committee on Addiction-Producing often inappropriately. It is not uncommon to apply Drugs (1964) has, in fact, recommended substitution the term addiction to any misuse of drugs outside of of the term " drug dependence " for both of the medical practice, with a connotation of serious terms drug addiction and drug habituation. This harm to the individual and to society, and often recommendation has been endorsed by the WHO with a demand that something be done about it. Scientific Group on Evaluation of Dependence- Such broad use can only create confusion and Producing Drugs (1964) and has been concurred in misunderstanding when abuse of drugs is discussed and supported, inter alia, by the Committee on from different viewpoints. Drug Addiction and Narcotics of the National The difficulties in terminology become increas- Academy of Sciences-National Research Council ingly apparent with the continuous appearance of (USA).8 new agents with various and perhaps unique phar- Drug dependence is a state of psychic or physical macological profiles, and with changing patterns dependence, or both, on a drug, arising in a person of use of drugs already well known. These develop- following administration of that drug on a periodic ments must be considered in their relation to, but or continuous basis. The characteristics of such a may not be adequately characterized by, current state will vary with the agent involved, and these definitions of addiction. There is scarcely any agent characteristics must always be made clear by desig- which can be taken into the body to which some nating the particular type of drug dependence in each specific case; for example, drug dependence of 1 " Drug addiction is a state of periodic or chronic intoxication produced by the repeated consumption of a morphine type, of barbiturate type, of amphetamine drug (natural or synthetic). Its characteristics include: type, etc. (1) an overpowering desire or need (compulsion) to continue The specification of the type of dependence is taking the drug and to obtain it by any means; (2) a tendency to increase the dose; (3) a psychic (psychological) and essential and should form an integral part of the generally a physical dependence on the effects of the drug; new terminology, since it is neither possible nor (4) detrimental effect on the individual and on society." even desirable to delineate or define the term " Drug habituation (habit) is a condition resulting from drug the repeated consumption of a drug. Its characteristics dependence independently of the agent involved. include: (1) a desire (but not a compulsion) to continue It should also be remembered that it was the desire taking the drug for the sense of improved well-being which it engenders; (2) little or no tendency to increase the dose; to achieve the impossible and define a complex (3) some degree of psychic dependence on the effect of the situation by a single term (" addiction " or " habiA drug, but absence of physical dependence and hence of an abstinence syndrome; (4) detrimental effects, if any, primarily, on the individual." 3Twenty-sixth Meeting, Washington, D.C., 1964. DRUG DEPENDENCE: ITS SIGNIFICANCE AND CHARACTERISTICS 723 tuation ", respectively) which has given rise to In this situation, there is a feeling of satisfaction and confusion in many cases. Therefore, the description a psychic drive that require periodic or continuous of drug dependence as a state is a concept for administration of the drug to produce pleasure or clarification and not, in any sense, a specific defini- to avoid discomfort. Indeed, this mental state is tion. the most powerful of all of the factors involved in It must be emphasized that drug dependence is a chronic intoxication with psychotropic drugs, and general term that has been selected for its applicabil- with certain types of drugs it may be the only factor ity to all types of drug abuse and thus carries no involved, even in the case of most intense craving connotation of the degree of risk to public health and perpetuation of compulsive abuse. or need for any or a particular type of drug control. Some drugs also induce physical dependence, The agents controlled by international treaties and which is an adaptive state that manifests itself by by national narcotics laws continue to be those that intense physical disturbances when the administra- are morphine-like, cocaine-like, or cannabis-like, tion of the drug is suspended or when its action is the use of which may result, respectively, in drug affected by the administration