A Trial to Evaluate the Safety, Efficacy, and Tolerability of Brexpiprazole in Treating Agitation Associated With Dementia of the Alzheimer's Type

Inclusion Criteria: * Participants with a diagnosis of probable Alzheimer's disease. * Participants with a diagnosis of agitation * Participants with a MMSE score of 5 to 22, inclusive, at screening and baseline visits. * Participants with a previous MRI or CT scan of the brain, that was performed after the onset of symptoms of dementia, with findings consistent with a diagnosis of Alzheimer's disease. * Participants who are residing at their current location for at least 28 days before screening and are expected to remain at the same location for the duration of the trial. * Institutionalized participants with an identified caregiver who has sufficient contact (minimum of 2 hours per day for 4 days per week) to describe the participant's symptoms and has direct observation of the participant's behavior. Non-institutionalized participants may not be living alone and must have an identified caregiver who has sufficient contact (minimum of 2 hours per day for 4 days per week) to describe the participant's symptoms and has direct observation of the participant's behavior. * Participants with onset of symptoms of agitation at least 2 weeks prior to screening visit. * Participants will and able to discontinue all prohibited concomitant medications to meet protocol required washouts prior to and during the trial period. Exclusion Criteria: * Participants with dementia or other memory impairment not due to Alzheimer's disease. * Participants with a history of stroke, well-documen…