There is much confusion and controversy in both the scientific and lay literature regarding the terms used in addiction research, including ''addiction," "abuse," and even what should be called a drug. The effect of multiple definitions and confusing terminology should not be underestimated; the committee itself struggled with these controversies.

One of the debates in the field is whether addiction is best defined as a disorder, a chronic disease, a complex set of symptoms, or a behavioral condition. This and other IOM committees have defined drug addiction as a brain disease similar to other chronic, relapsing conditions, such as heart disease and diabetes, and manifested by a complex set of behaviors that are the result of genetic, biological, psychosocial, and environmental interactions (IOM, 1995, 1996).1

Medical diagnostic systems have defined addiction as compulsive use of a drug that is not medically necessary, accompanied by impairment in health or social functioning (APA, 1994; WHO, 1992).2 The term "substance dependence" is used by these classification systems as equivalent to addiction, but the term dependence is often confused with other aspects of addiction. For example, it is sometimes considered to be synonymous with the term "tolerance," a physiological process in which repeated doses of a drug over time elicit a progressively decreasing effect and the person requires higher or more frequent doses of the drug to achieve the same results. There are situations in which tolerance can be present in the absence of compulsive craving; for example, a person being treated with morphine for chronic pain. However, few such individuals become pathologically addicted; once treatment is no longer needed, they do not engage in compulsive drug-seeking behavior.


One committee member, Dr. Satel, disagreed with this definition. She believes that, "The concept of addiction as a brain disease is somewhat limited and potentially misleading. Many workers find it more instructive to define addiction as a complex behavioral condition that is accompanied by organic changes in the brain but which is not inevitably sustained by them.

In conventional brain disorders such as schizophrenia or Parkinson's disease, symptoms of disturbed mentation and action are the result of brain pathology. In compulsive drug use, conversely, the brain changes are a result of that behavior. These changes, it is true, likely predispose to craving and rapid re-habituation in individuals who have been drug free, thus making them vulnerable to relapse. Yet it is important to emphasize that the course of addiction can be modified by its consequences and that biological urges can be overridden. The addiction as a brain disease model tends to obscure this clinical reality."


Drug use is not defined in either system as a medical disorder. Abuse, or harmful use, is mentioned in these systems as being characterized by higher use accompanied by legal, social, or interpersonal problems.

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement