Prevalence of benzodiazepine abuse and dependence in psychiatric in-patients with different nosology. An assessment of hospital-based drug surveillance data.

Frequencies of abuse and dependence assessed continuously within a drug surveillance system were analysed as a contribution to risk-benefit evaluations of benzodiazepines (BZDs). In 4.7% of 15,296 patients admitted to psychiatric hospitals between 1980 and 1985, BZDs had been involved in some kind of abuse or dependence. Primary BZD dependence, defined as physical dependence on BZDs in patients who had not been dependent before, was observed in about 1% of admitted patients. Linking these data with psychiatric diagnoses revealed a high risk of primary BZD dependence for in-patients (11.8%) with anxiety neurosis (ICD-9, 300.0), and a lower risk for neurotic (300.4) and for endogenous depressives (296.1) (risk 3.7% and 2.7% respectively). Older age was also related to primary BZD dependence. For depressive in-patients, the risk was twice as high in females as in males. Anecdotal observations advocate more systematic investigation of the emotional effects of long-term therapy with BZDs.