exposure. Early research applied a narrow traditional epidemiological framework to the study of heroin use (de Alarcon, 1969; Hughes and Crawford, 1972); however, recent studies employ a broader concept of epidemiology in which both descriptive and analytic epidemiological studies are used to address the problems of drug use and abuse in society.
Epidemiological research provides information essential for defining the scope of the problem by identifying populations at risk. Epidemiological data on trends in illicit drug use and abuse over time help to measure the effectiveness of the national drug control program. Epidemiological research provides insights into the etiology of drug initiation and use (Chapter 5). Additionally, epidemiological research provides information on the nature and extent of the multiple consequences of drug abuse (Chapter 7). Data on drug availability and demographics allow prevention and treatment programs to target the needs of those populations identified as at risk for increased alcohol and illicit drug use.
This chapter describes the variety of data systems currently in place that address different aspects of the drug use problem in the United States and discusses accomplishments and future directions in epidemiological research.
One way in which the epidemiology of drug abuse differs from more traditional epidemiological studies of infectious diseases is that drug abuse is not universally accepted as a medical condition. As indicated in Chapter 1, there are differences of opinion about applying the medical model to drug abuse. Researchers and clinicians commonly distinguish three levels of drug behavior: use, abuse, and dependence (see Chapter 1 and Appendix C). The stages of abuse and dependence are most clearly amenable to a diagnostic perspective, whereas the use stage is more readily characterized by its frequency, quantity, and duration. Therefore, use is generally the stage most easily and accurately measured outside clinical practice as described by epidemiological research. A complication in research, however, is that different drugs have different patterns of use, and the transition from use to abuse to dependence may be very different for different drugs (e.g., heroin as compared to marijuana).
Clearly, one of the major accomplishments in epidemiology has been to establish a variety of data systems that measure different aspects of drug use and abuse. Two major data systems provide broad-based statis-