Data presented by Dr. Allain indicated that benzodiazepines are associated with an increased risk of Alzheimer's disease (AD). Dr. Cohen asked whether any mechanism had been proposed for this finding. “No mechanism was proposed by the investigators,” said Dr. Allain. He noted that the investigators in this study, which has now enrolled more than 5,000 patients, are analyzing drug use among patients before and during the study. He also pointed out that the finding of an association between benzodiazepines and AD contrasts with the results of a previous trial, which found no such association.