Apolipoprotein-E (APO-E) genotype and symptoms of psychosis in Alzheimer's disease.

The authors examined the association of Apolipoprotein-E (APO-E) genotype to symptoms of psychosis and depression in 501 patients diagnosed with probable (n=343) or possible (n=158) Alzheimer's disease (AD) according to NINCDS-ADRDA criteria. They observed the following APO-E genotypes: epsilon2/epsilon3 (n=19); epsilon2/epsilon4 (n=14); epsilon3/epsilon3 (n=228); epsilon3/epsilon4 (n=203); epsilon4/epsilon4 (n=37). In contrast to previous reports, the results did not indicate a relationship between either the epsilon4 allele or the epsilon2 allele and symptoms of mood disturbance in AD. However, an elevated risk for psychosis was shown, specifically, at the severe stage of cognitive impairment, among AD patients carrying the epsilon4 allele, after effects of age, gender, education, and level of cognitive impairment were controlled.