Negative symptoms in Alzheimer's disease: a confirmatory factor analysis.

Objective To examine different conceptual models of negative symptoms in Alzheimer's disease. Design Confirmatory factor analysis of cross-sectional data. Subjects Alzheimer patients (n =281) admitted to a psychogeriatric observation ward. Materials Nurses' Behavioural observation scale for psychogeriatric inpatients (GIP). Global clinical ratings of severity of dementia and depression based on the Cambridge Examination for Mental Disorders of the Elderly-Dutch version (CAMDEX-N). Results A unidimensional model of dementia fitted the data poorly. Multidimensional models produced better results. In two- and three-factor models negative symptoms were separated from cognitive impairment and mood disturbances. The more severe the memory impairment, the more socially withdrawn patients were. In this sense negative symptoms may have been secondary to cognitive decline. However, no association was found between negative symptoms and mood disturbances. Conclusions Negative symptoms are a prominent clinical feature of Alzheimer's disease and they are related to memory impairment but not to mood disturbances. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]