Study Evaluating TheSafety And Efficacy Of PF-05212377 Or Placebo In Subjects With Alzheimer's Disease With Existing Neuropsychiatric Symptoms On Donepezil

Inclusion Criteria

• •Clinical diagnosis of probable AD with supportive brain imaging documentation
• •Have existing neuropsychiatric symptoms as defined by a score equal or greater than 10 on the NPI at screening, arising from item scores equal or greater than 2 (frequency X severity) on at least 2 domains.
• •Has been on donepezil (stable dose of 5 mg or 10 mg) for at least four months, with no intent to change such for the duration of the study.