A Randomized, Placebo-Controlled Trial to Examine the Efficacy of Oral Donepezil in Subjects With MCI

Inclusion Criteria: * Healthy males or females ages 55-90 inclusive (Healthy is defined as no clinically relevant abnormalities identified by a detailed medical history, full physical examination, including blood pressure and heart rate measurement, 12-lead ECG and clinical laboratory tests) * Body Mass Index (BMI) between 18 to 34 kg/m2, inclusive; and a total body weight * Subjects with mild cognitive impairment (MCI) must have a reliable informant who has an average of 10 hours per week or more contact with the subject. * Memory complaints and memory difficulties, which are verified by an informant * Mini-mental status exam (MMSE) score of 24-30 Exclusion Criteria: * Subjects with known hypersensitivity to donepezil hydrochloride or to piperidine derivatives * Insulin-requiring diabetes or uncontrolled diabetes mellitus * Subjects with a current diagnosis of depression or other psychiatric illnesses