Impairment of performance associated with long-term use of benzodiazepines

The long-term effects of benzodiazepines (BDZ) on psychomotor and cognitive functions were assessed in 28 outpatients, users of low therapeutic doses of diazepam (13.6+/-4.9mg/day, range: 5-20mg/day) for 5-20 years (10.1+/-5.0 years). These patients' performance was compared with two control groups: 53 BDZ-free anxious outpatients and 56 healthy volunteers. The three groups were similar in sex, age and education. BDZ chronic users were tested before and after short-term (3 weeks) and long-term discontinuation (at an average of 10 months). Performance of chronic users of BDZ was consistently worse than those of the control groups, suggesting an impairment in these patients on both psychomotor and cognitive functions. These were not related to either dose or cumulative exposure to BDZ, and were also independent of diagnosis and levels of anxiety and depression. Moreover, these deficits were persistent as their performance failed to improve after drug discontinuation.