Prevalence and correlates of Capgras syndrome in Alzheimer\u27s disease.

OBJECTIVES: This study examined the prevalence and clinical correlates of Capgras syndrome (CS) in Alzheimer\u27s disease. DESIGN: Cross-sectional study of elderly patients evaluated at an outpatient memory disorders clinic classified according to the presence or absence of CS. SUBJECTS: One hundred and fifty-one consecutive patients diagnosed with probable (N=110) or possible (N=48) Alzheimer\u27s disease (AD) utilizing NINCDS-ADRDA diagnostic criteria. MATERIALS: The Behavioral Pathology in Alzheimer\u27s Disease Rating Scale (BEHAVE-AD), Mini-Mental State Examination (MMSE) and Blessed Dementia Scale (BDS). RESULTS: CS was observed in 10% of the sample (N=16). Associated factors included other delusions, lower MMSE scores and higher BDS scores. The relation between CS and both cognitive and functional status remained significant after controlling for other delusions. CONCLUSION: CS was prevalent in approximately 10% of our community-dwelling AD sample. This syndrome was more common at the later stages of the illness and showed relations with increased functional impairment and other psychotic symptomatology