The effects of benzodiazepines on cognition.

Initially thought to be virtually free of negative effects, benzodiazepines are now known to carry risks of dependence, withdrawal, and negative side effects. Among the most controversial of these side effects are cognitive effects. Long-term treatment with benzodiazepines has been described as causing impairment in several cognitive domains, such as visuospatial ability, speed of processing, and verbal learning. Conversely, long-term benzodiazepine use has also been described as causing no chronic cognitive impairment, with any cognitive dysfunction in patients ascribed to sedation or inattention or considered temporary and associated with peak plasma levels. Complicating the issue are whether anxiety disorders themselves are associated with cognitive deficits and the extent to which patients are aware of their own cognitive problems. In an attempt to settle this debate, meta-analyses of peer-reviewed studies were conducted and found that cognitive dysfunction did in fact occur in patients treated long term with benzodiazepines, and although cognitive dysfunction improved after benzodiazepines were withdrawn, patients did not return to levels of functioning that matched benzodiazepine-free controls. Neuroimaging studies have found transient changes in the brain after benzodiazepine administration but no brain abnormalities in patients treated long term with benzodiazepines. Such findings suggest that patients should be advised of potential cognitive effects when treated long term with benzodiazepines, although they should also be informed that the impact of such effects may be insignificant in the daily functioning of most patients.