The epidemiologic triangle focuses on the host, agent, and environment as a paradigm for prescription drug abuse and addiction. The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, provides the most appropriate system for describing drug abusers. The subsequent chapters in the volume review the main categories of psychoactive drugs, discuss their pharmacological and behavioral effects on users, and describe a series of types of prescription drug users based on a psychological and motivational perspective. Additional chapters examine the medical and legal aspects of benzodiazepines, discuss the problem of interviewing difficult and uncooperative clients who may have an ulterior motive or hidden agenda for seeking professional help, and present a diagnostic and evaluation approach for assessing clients. Further chapters review diagnostic issues related to the diagnosis of psychiatric disorders (anxiety, panic, and mood disorders) and drug abuse; describe the range of treatment opportunities available to prescription drug abusers and other drug abusers; and discuss the legal responsibilities of health care providers and clients, civil and criminal offenses and remedies, and guidelines for appropriate prescribing practices. The concluding chapter emphasizes that although prescription drug abuse amounts to a relatively small part of contemporary drug abuse, it is statistically and clinically significant. Table and 23 references