The authors tested the hypothesis that behavioral disturbances are reported at significantly lower rates by caregivers of Alzheimer's disease (AD) patients receiving the antidementia drug donepezil, compared with a group of patients receiving no antidementia drug treatment. Patients administered donepezilfor 6 months (n=84) were compared with patients not on donepezil (n=248). Patients taking donepezil had significantly lower levels of behavioral disturbances than patients not receiving this agent (P< or =0.011). Specifically, donepezil patients were described as significantly (P< or =0.05) less likely to be threatening, destroy property, and talk loudly. Also, significantly fewer patients receiving donepezil were treated with sedatives (P< or =0.005). These findings support the growing body of evidence that cholinesterase inhibitors have psychotropic properties and reduce behavioral disturbances in patients with AD.