INTRODUCTION<br > The use， misuse， and abuse of psychoactive chemicals in one forte<br >or another has been present in almost all societies since the beginnin~<br >of recorded civilization. These chemicals， called {among other things ，<br >spirits， tonics， medication， drugs， or substances of abuse， have beer<br >widely used in a variety of religious， experimental， medical， and social<br >contexts. By and large， they have been used effectively and accom<br >plished the purpose for which they were intended， for example， the<br >relief of pain or anxiety; the induction of relaxation and sleep; an intox.<br >ication euphoria; or the development of an altered state of con.<br >sciousness for religious or experimental purposes.<br > Since the turn of the century， and especially within the past 2~<br >years， there has been a rapid proliferation of synthetic and semisyn<br >thetic psychoactive substances used， the numbers of people usin~<br >them， and the variety of usage patterns， particularly multiple ol<br >polydrug use and abuse. All of this has led to a phenomenology ol<br >chemical use that is particularly complex. Attempts to simplify il<br >through unifying concepts or sweeping generalizations tend to increase<br >the misconceptions and confusion.<br > Inconsistency and lack of clarity also exist in the use of ter-<br >minology. For example， drug abuse for some people means only opiate<br >addiction， whereas for others it is opiate addiction and the use of so.<br >called "soft" drugs. For still others， it encompasses any substance thai<br >has abuse potential， including alcohol. For many who would like to see<br >a unification of programs and services， the generic concept of chemical<br >dependence or substance abuse has replaced the drug-specific concepl<br >of alcoholism or opiate addiction. For others， the one-drug-one.<br >problem concept has persisted. This may be difficult to justify in light<br >of recent evidence that polydrug， rather than monodrug， abuse ha.，<br >become an important pattern of usage， particularly in terms ot<br >emergency room visits (see Chapter 5}. Confusion also occurs because<br >substantive issues often become tainted with an emotionality thai<br >blurs objectivity. This is particularly important since funding fol<br >research， treatment， prevention， and training for both alcoholism and<br >drug abuse often comes from the same limited budget.<br > Another factor that has obscured clarity in these areas is the lack ot<br >a theoretical framework for understanding the dynamic process<br >of alcohol or drug dependency. For example， a moral model in which<br >alcohol and other drugs are either good or bad; a judicial model in<br >which they are legal or illegal; or a purely biomedical model in which<br >alcoholism may be a disease but sedative-hypnotic abuse is not， are all<br >of little assistance. Attempts to correlate specific personality types<br >with a oarticular drue nf abuse alsn has nnt nrnven very fruitful， since<br >