Drug abuse has been called the nation's number one public health problem. Of the nation's personal health care expenditures, $1 of every $12 is spent on prevention, diagnosis, and treatment of people suffering from addictive diseases. The measurable total economic costs of drug addiction clearly are enormous, totaling $256.8 billion in 1990. Alcohol use, abuse, and addiction, including the direct costs of crime, motor vehicle crashes, and other related costs, comes at the highest cost, estimated at $98.6 billion. The cost of nicotine addiction follows ($91.3 billion), and then addiction to illegal drugs ($66.9 billion).
Recent discoveries have turned addiction research into a field that should attract the very best scientists interested in both basic and translational research. Researchers have cloned the brain receptors (i.e., the immediate molecular targets) for all significant drugs of abuse and have defined their locations in the brain. Of great significance, there is now general agreement on the importance of the dopaminergic brain reward pathway as one of the key common sites of action of addictive drugs. Some aspects of treatment for all drugs are beginning to capitalize on the identification of this common pathway and the systems that regulate it. Researchers can now turn to the very difficult problems of understanding the precise brain mechanisms by which drugs alter brain function and come to dominate behavior. In the process, a great deal will be learned about the normal control of motivation and emotion in the brain. With such discoveries, understandings about other human diseases and illnesses can also be gained. For example, dopamine systems are not only the substrates of drug abuse and addiction, but are also involved in a variety of psychiatric disorders and some movement disorders, such as Parkinson's disease.
The importance of these findings notwithstanding, it must be emphasized that drug addiction is the result of interacting biological, behavioral, social, and environmental factors. Thus, the development of successful treatments can come only from integrative, multidisciplinary research that may provide stronger connections between research and clinical practice.
How does the use of tobacco, alcohol, opioids, and stimulants begin? Virtually all Americans, some of whom may have a genetic vulnerability to drug abuse, are faced with the decision of whether to smoke, drink alcohol, or take illicit drugs. Why do some individuals say yes and others refuse? In addition to studies about genetic vulnerabilities, these and similar questions are the focus of behavioral, epidemiological, and social science research aimed at understanding