Until the late 1980's, physical dependence and the development of tolerance were considered the key criteria by which to evaluate a drug's potential for abuse. The Merck Manual, for example, defines the following terms in the introduction to its Drug Dependence section: drug dependence of a specific type, addiction, drug abuse, recreational drug abuse, psychological dependence, physical dependence, tolerance, and withdrawal syndrome. (5) While the Merck Manual utilizes these terms according to precise definitions, the widespread use of these terms among the general population has distorted their meanings from their original clinical origins. According to one expert writing in 1992:

"This has been a major source of confusion in the scientific exploration of the dependence potential or liability of drugs and the manner society reacts to this problem. The terms drug abuse, drug addiction, drug misuse or drug dependence are often used interchangeably in defining the problem."(6)

Thomas Cicero is the chairman of the Drug Evaluation Committee (DEC) of the College on Problems of Drug Dependency (CPDD). The CPDD evaluates drugs for dependence liability for the National Institute on Drug Abuse (NIDA). The CPDD's scientific task is to maintain and apply standardized tests for measuring the dependence liability of drugs. The standardization of their tests provides a scientific data base that facilitates equal application of the provisions of the Controlled Substances Act to pharmaceutical drugs and substances.

The problem with the term drug abuse is that it

"is far too subjective to have any true significance or validity in that it means different things to different people and it is difficult to establish definitive criteria to define it. For example, this term frequently conveys social approval of the use of a drug. Clearly, using social approval alone, drug abuse varies from culture to culture and from time to time. As an example . . .in many countries the use of marijuana is legal and/or condoned and is therefore socially acceptable behavior, although in scientific terms it fulfills all of the criteria for dependence potential. Finally, the use of certain drugs in our own culture has been viewed as abuse at certain times and socially acceptable at others; alcohol and cocaine use are good examples of this phenomenon and illustrate the danger associated with using social approval alone as a criterion to classify a drug as having a significant abuse potential."(7)

The term drug addiction suffers from many of the same problems. The term non-medical use of drugs "should be dropped from the scientific analysis of the dependence liability of drugs, since it confuses rather than clarifies any issues."(8)

This concern for terminology is not new. Joseph Brady is affiliated with the Behavioral Biology Research Center of the Johns Hopkins University, and is a prominent member of the CPDD. At the annual meeting of the CPDD in 1987, Brady complained about

"the deplorable state of the nomenclature in this muddled arena of drug and alcohol "addiction". "dependence", "abuse" or whatever! The interchangeable, quasi-technical use of these terms as referents for a bewildering range of phenomena and experimental pseudo-phenomena continue to produce a degree of semantic and taxonomic confusion that is perpetuated in even the most current and authoritative treatments of the subject by friends and relatives alike. The terms themselves, persistently reified as substantive noun "things" that enter into subject-predicate relationships with other "things" (and affect, as well as are in turn affected by these other "things"), are seldom accorded appropriate conceptual status as constructs emerging from observed relationships between specifiable antecedents (biological and social) and definable consequences (biochemical, physiological, and behavioral). Within this relational context, the analysis of interacting biological and behavioral events would seem to provide a basis for defining these constructs more operationally and specifying the conditions under which a unifying conceptual framework can be developed for this prominent aspect of substance use and misuse."(9)