Is benzodiazepine use a risk factor for cognitive decline and dementia? A literature review of epidemiological studies

Background. A major public health issue is to determine whether long-term benzodiazepine use may induce cognitive deficits persisting after withdrawal. The aim of the present review was to examine findings from prospective studies carried out in general population samples exploring whether exposure to benzodiazepines is associated with an increased risk of incident cognitive decline. Method. Using a MEDLINE search and a hand-search of related references in selected papers, we retrieved original studies published in peer-reviewed journals that explored in general population samples the association between benzodiazepine exposure and change in cognitive performance between baseline and follow-up assessment. Results. Six papers met the inclusion criteria. Two studies reported a lower risk of cognitive decline in former or ever users, two found no association whatever the category of user, and three found an increased risk of cognitive decline in benzodiazepine users. Conclusions. The discrepant findings obtained by studies examining the link between benzodiazepine exposure and risk of cognitive decline may be due to methodological differences, especially regarding the definitions of exposure and cognitive outcome. As a large proportion of subjects are exposed to benzodiazepines, a small increase in the risk of cognitive decline may have marked deleterious consequences for the health of the general population. This issue needs to be explored further by pharmaco-epidemiological studies.