Alzheimer disease (AD) and most other late-onset dementing illnesses are progressive, passing through stages of mild cognitive impairment to mild, moderate, and severe dementia. Clinically, patients in moderate to severe phases of AD have more marked cognitive changes, more severe impairments in activities of daily living (ADL), and are less able to attend to their own needs; in addition, they undergo more severe behavioral changes.1 Patients in the moderate to severe stage of AD are also more likely to be resident in nursing homes in world economies where nursing homes are widely available and commonly used.2 Patients in the moderate to severe stages of dementia are more likely to exhibit mixed pathology with combinations of cerebrovascular disease and degenerative changes, to have more medical co-morbidity with age-related disease,3 and to take more medications to control their medical illnesses. The measurement of neuropsychiatric symptoms in moderate to severe AD is particularly important. Fully characterizing these symptoms is a prelude to addressing key issues, such as when these symptoms occur and what their triggers might be. This information allows appropriate nonpharmacologic and pharmacologic interventions to be instituted. The dominant behavioral and psychiatric symptoms in moderate to severe AD are delusions, depression, anxiety, agitation, and restlessness.4 The prevalence of dementia-associated mental and behavioral disturbances was assessed in a population-based study of 5,092 community-dwelling individuals aged 65 years or older.5 Patients were assessed for cognitive impairment using the Mini-Mental State Examination (MMSE). For those who were classified as having possible or probable AD, disease severity was determined by the Clinical Dementia Rating (CDR) scale.6 Psychopathology was assessed using the Neuropsychiatric Inventory (NPI).7 A higher occurrence of apathy, depression, and agitation/aggression was found in individuals with dementia than in those without dementia. Participants with AD were more likely …