The process or state in which an organism needs the presence of a DRUG (including ALCOHOL) to function normally. The concept and definition of addiction has undergone considerable evolution throughout recent history. Central to this process has been the role of volition or ‘will’ of the addicted individual and of personal responsibility. Before the nineteenth century, addictions were generally considered as vice, sin, or moral failings. It was recognized that certain substances led to undesirable ‘habits,’ but it was generally thought that drinking, for example, was something over which the individual had ultimate control; that is, drinking to excess was an individual choice. The notion that ALCOHOLISM (and eventually, drug addiction) was more like a disease than wilful immoral behaviour has its roots in the nineteenth century. Thomas Trotter wrote in 1804 that ‘the habit of drunkenness is a disease of the mind’. In this century, the MEDICAL MODEL (or the DISEASE MODEL) of alcoholism and other drug addictions has been most influential. The addict is viewed as a patient with a disease, in need of medical or psychiatric treatment. Detractors of this view argue that that the disease concept has actually caused addictive behaviour to increase because it excuses uncontrolled behaviours and allows people to interpret their lack of control as the expression of a disease they can do nothing about. However, there is now strong evidence that many addictive drugs, including COCAINE, alcohol, HEROIN, AMPHETAMINE and NICOTINE can exert powerful long-term effects on the biochemical and molecular machinery of the brain. It is believed that many of these neuroadaptive phenomena (for example, long-lasting changes in GENE EXPRESSION and the SECOND MESSENGERS system) underlie the intense craving and relapse to drug use characteristic of addiction. Thus, while free choice is certainly involved in the decision to initiate drug-taking behaviour, the emotional and cognitive distress associated with dependence is in large part out of the individual’s control once the process of addiction has started.
Traditionally, the appearance of a physical WITHDRAWAL SYNDROME was essential in determining if someone was ‘addicted’ to a substance. For example, some years ago cocaine was not thought to be addictive because users experienced no apparent withdrawal syndrome during abstinence from the drug.
Today, physical signs of addiction are still important but not necessary for diagnosis. Several internationally accepted diagnostic criteria exist for drug dependence. The DSM-IV (Diagnostic and Statistical Manual of the American Psychiatric Association) criteria for psychoactive substance dependence emphasize clusters of symptoms or behavioural manifestations that clearly indicate distress or disability. These criteria reflect behavioural changes that would be considered as extremely undesirable in all cultures. There are three basic characteristics to this set of criteria: (1) loss of control over the use of the substance, (2) impairment in daily functioning and continued use of substance despite adverse consequences and (3) physical or emotional adaptation to the drug, such as in the development of tolerance or a withdrawal syndrome. The problem of defining drug abuse has also been considered by the World Health Organization (WHO), from the point of view of public health policy. The WHO model was instrumental in formulating the ‘dependence syndrome’ concept, which has gradually come to replace the terms ‘drug addiction’ and ‘drug abuse’. In 1981, the WHO committee defined the DEPENDENCE SYNDROME as ‘a cluster of physiological, behavioural, and cognitive phenomena in which the use of a substance or a class of substances takes on a much higher priority for a given individual than other behaviours that once had higher value’. A central descriptive characteristic of the dependence syndrome is the desire (often strong, sometimes overpowering) to take drugs, alcohol or TOBACCO. This model also emphasizes the high frequency of maladaptive behaviours, loss of control and neglect of alternative pleasures or interests in favour of substance use. Incorporated into the WHO definition is the concept of NEUROADAPTATION, in which the constant presence of the drug somehow induces long-lasting changes in the brain.
As is clear from both the DSM-IV and WHO criteria, modern concepts of drug addiction tend to emphasize the behaviour of the individual and the adverse consequences of such behaviour; they do not attempt to explain the dependence. These definitions fall within the framework of psychiatry and public health, and reflect current society’s general acceptance of drug dependence as a medical problem or disease.
Reference
Kelley A.E. (1995) Psychoactive substance use disorders. In Abnormal Psychology, eds. D. J.Rosenhan & M.E.P.Seligman, Norton: New York.
ANN E.KELLEY
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