Neuropsychiatric symptoms are common in patients with dementia or Alzheimer’s disease (AD).1-3 They include a broad range of symptoms from apathy, agitation, mood symptoms (dysphoria and anxiety), psychosis (delusions and hallucinations), to sleep and appetite disturbances. Some symptoms are clustered into syndromes, and provisional operational criteria, such as AD-related psychosis or depression, are proposed to facilitate their study.4,5 These symptoms have serious negative consequences for patients, including compromising quality of life and increasing impairment in activities of daily living. They are also major sources of psychological stress, depression, and burden for the caregivers.6 Studies have shown that these symptoms are linked to elder abuse and are important determinants of the institutionalization of patients with AD.7,8 Neuropsychiatric symptoms reflect the underlying neurobiological changes of the diseased brain, and many can be alleviated by psychotropic medications.9,10 Certain stage-specific patterns of the neuropsychiatric symptoms can be observed during the course of AD,11 and some symptoms may have specific value in the prediction of the disease course. For example, several studies have found that depression is a harbinger of AD;12,13 others have shown that delusions or hallucinations predict clinical or functional decline.14,15
Mild cognitive impairment (MCI) describes cognitive impairment in the elderly not of sufficient severity to meet diagnostic criteria for dementia. It is often a transitional state between normal aging and dementia. Subjects with MCI have memory impairment or other cognitive deficits that may be noticeable to their family. Objective cognitive tests show worse performance than their age-and education-comparable contemporaries. However, their daily function is generally preserved.