["alzheimer's disease"]
['placebo', 'donepezil', 'donepezil']

        Inclusion Criteria:

          -  Meets listed criteria for a diagnosis of probable AD

          -  Has a clearly documented history either in medical records or from an informant of
             cognitive decline over at least 6 months

          -  Has a reliable partner/caregiver who is willing to provide input by participating in
             assessments

          -  Has results of a physical examination and clinical laboratory tests within normal or
             clinically acceptable limits

          -  Can communicate with trial staff acceptably, possesses the ability to respond verbally
             to questions, follow instructions, complete questionnaires, and adhere to visit
             schedules

          -  Can read at a 9th grade level or equivalent, and has an acceptable history of academic
             achievement and/or employment

          -  Has a magnetic resonance imaging (MRI) scan that rules out non-AD conditions
             contributing to cognitive dysfunction

          -  Capably performs the CogState screening battery

          -  Has adequate visual acuity and function

          -  Females are not of childbearing potential

        Exclusion Criteria:

          -  Has ever received acetylcholinesterase inhibitors, memantine, or other symptomatic AD
             treatment including approved medical foods

          -  Has an uncontrolled, clinically significant medical condition or situation within 3
             months prior to screening

          -  Has had major surgery within 3 months prior to screening

          -  Has tested positive for human immunodeficiency virus (HIV) or has evidence of an
             active hepatitis B infection

          -  Has a history of malignancy within the prior 5 years

          -  Is unwilling or ineligible to undergo an MRI scan

          -  Has a history of clinically important structural changes on screening MRI scan

          -  Has a clinically important history of stroke or a diagnosis of vascular dementia

          -  Has evidence of a clinically relevant non-AD neurological disorder

          -  Has a history of head trauma, or serious infectious disease affecting the brain within
             the prior 3-5 years

          -  Has evidence of a clinically relevant or unstable psychiatric disorder, excepting
             major depression in remission

          -  Has evidence of a current episode of major depression

          -  Has evidence of Type 4 or Type 5 Suicidal Ideation

          -  Has clinically significant vitamin B12 or folate deficiency in the 6 months prior to
             screening

          -  Is pregnant, attempting to become pregnant or is nursing children

          -  Has used any investigational drug or participated in any other clinical trial within
             the prior 30 days

          -  Has a history of alcoholism or drug dependency/abuse within the last 5 years

          -  Has a relative contraindication to donepezil including sick sinus syndrome, third
             degree heart block, active gastrointestinal (GI) bleeding, Zollinger-Ellison syndrome,
             uncontrolled peptic ulcer disease, or uncontrolled asthma
      