Over a period of five and a half years, 792 inpatients with benzodiazepine (BZD) abuse and dependence in accordance with the WHO definition were registered at a university psychiatric hospital. One-quarter of them abused BZD exclusively, while three-quarters suffered from polytoxicomania or were alcohol dependent as well. It was possible to distinguish two groups of patients: one with primary, mainly low-dose, dependence preferring lorazepam and the other with secondary, often high-dose, dependence with diazepam as the main drug. In 108 patients with isolated BZD dependence, withdrawal symptoms of somatic, psychological, or perceptual quality were observed. The severity of the withdrawal syndrome seemed to depend on the time of consumption, dose, mode of withdrawal, and type of BZD compound. Following abrupt cessation, 11 patients with long-standing dependence on high BZD doses developed withdrawal psychoses, presenting a delirious, paranoid-hallucinatory, or depressive-anxious syndrome.