Features of potentially reversible dementia in elderly outpatients.

A standardized evaluation was carried out in two separate groups of patients with dementia to determine the features that characterize those with potentially reversible or treatable dementia. In both groups, Alzheimer's-type dementia was the most common diagnosis (65% and 70%); the most common cause of potentially reversible cognitive impairment was medication toxicity. In both groups, patients with potentially reversible dementia had a shorter duration of symptoms, less severe dementia and used more prescription drugs. Because of this association, these features may be considered risk factors but are not distinguishing or diagnostic features of patients with potentially reversible dementia. Other, previously undetected, treatable illnesses not often considered in the differential diagnosis of potentially reversible or treatable dementia were also prevalent in these patients.