The current widespread nontherapeutic use of psychoactive drugs began among a small group of college students in the early 1960s. It spread with explosive force into an epidemic of extraordinary scope involving all regions of the country, all socioeconomic classes, and all age groups. This article reviews the drugs currently used and identifies those who use them. It discusses the complex, rapidly changing patterns of use and the consequences of this epidemic for both the individual and the society. The inhalants, phencyclidine, cocaine, heroin, the psychotherapeutics (methaqualone and amphetamine), and marijuana are the most widely used drugs. Recent clinical and laboratory research indicates that these drugs pose serious hazards to physical and mental health. Marijuana is the most widely used illicit drug; one quarter of the entire U.S. population have used the drug, and 20 million people use it daily. The short-term and long-term adverse effects of marijuana have important social implications. Recent data suggest that drug users possess limited inner resources to cope with psychological stress and that they take drugs to fill a moral and spiritual void and to meet intense emotional needs. It is proposed that these character traits and emotional conflicts of drug users may reflect recent changes in child rearing and family stability.