Long-term, normal-dose benzodiazepine treatment was discontinued in 16 patients who were suspected of being dependent on their medication. The withdrawal was gradual, placebo-controlled, and double-blind. All the patients experienced some form of withdrawal reaction, which ranged from anxiety and dysphoria to moderate affective and perceptual changes. Symptom ratings rose as the drugs were discontinued, but usually subsided to prewithdrawal levels over the next two to four weeks. Other features of the withdrawal included disturbance of sleep and appetite and noticeable weight loss. Electroencephalography showed appreciable reduction in fast-wave activity as the drugs were withdrawn, and an improvement in psychological performance was recorded by the Digit Symbol Substitution Test. Because of the risk of dependence on benzodiazepines these agents should probably not be given as regular daily treatment for chronic anxiety.