Life scientists have declared the 1990s to be the "Decade of the Brain." Undoubtedly the most important organ, the brain is perhaps the least understood. Until recently, the proper methodology for exploring the basic functions of the brain were not available. However, the new era of computer technology brain imaging and molecular biology have given scientists the tools for studying previously hidden mechanisms of the brain which control thinking, emotions, and behavior. Along with this new knowledge, scientists have observed that drugs of abuse can alter these same brain functions in a profound and persistent manner. Drugs of abuse are widely used substances that differ in chemical nature but have a common property-creating dependence. Dependence is characterized by a stereotypical pattern of behavior oriented toward the search, acquisition, and ingestion of drugs of abuse with such frequency and in such quantity as to be harmful. This behavior is beyond the control of reason and will. Studies conducted during the "decade of the brain" or before, show that the clinically observed, dependent behavior induced by drugs of abuse result from neurophysiological and chemical alterations of complex brain mechanisms. These mechanisms involve the production and turnover of the brain neurotransmitters that carry information in the brain neurocircuitry, changes in brain metabolism and circulation, and alterations in the expression of DNA which programs the functions or the neuronal cell. This book describes a number of newly discovered basic brain mechanisms and the alterations caused by drugs of abuse. Contributions by top researchers in fields of radian biology, biochemistry, genetics, and pharmacology examine the new technological improvements for the measurement of brain function, metabolism, blood flow and drug elimination and report changes in brain biochemistry, including DNA expression, as they occur during drug abuse. Physicians and health professionals will benefit from a better understanding of the effects of drugs on the brain which will lead to more effective interventions for prevention and treatment. Highlights include: New knowledge about the brain New methods of investigation Opiates and the brain Marijuana and the brain Cocaine and the brain This book will be of interest to health professionals and program administrators involved in the education and treatment of substance abuse disorders, as well as physicians, nurses, psychiatric social workers, neuroscientists, and pharmacologists.