Benzodiazepines and risk of dementia: true association or reverse causation?

According to a recently published population study conducted in France, exposure to benzodiazepines may be associated with an approximately 50% increase in the risk of dementia in the elderly. However, the clinical interpretation of this finding raised some concerns. A causal link between benzodiazepine use and diagnosis of dementia may be real, but it is nevertheless possible that the increased risk might be due to other confounding factors. In this article, the main strengths and weaknesses of this study are briefly analysed, including the possibility of reverse causation. Implications for research and current practice are discussed.