The benzodiazepines were developed in the 1950s, some introduced in the 1960s, and many more since then. Pharmacologically, they are sedative/hypnotics akin to alcohol, chloral, the barbiturates, and meprobamate. All have been widely used both within and outside the licit medical context. Usage of benzodiazepines increased dramatically during the 1960s and early 1970s; tranquilizer but not hypnotic usage has since declined. Both abuse and misuse were documented early, but the incidence was deemed low in view of the widespread prescription. Normal-dose physical dependence was first suspected in the early 1970s but it was not until the early 1980s that scientific evidence was adduced to establish its reality and frequency. Further studies have revealed the complex nature of the withdrawal syndrome. A reaction has set in against these drugs, with attempts to limit them to short-term use.