Psychosis, serotonin receptor polymorphism and Alzheimer's disease

Several studies have shown that psychotic symptoms appear in the course of the disease of a large portion of Alzheimer's disease (AD) patients. The ai m of this study is to analyze the segregation of the 102T/C 5-HT2A, seroton in receptor gene polymorphism in patients affected by sporadic AD with and without psychotic symptoms. A total of 155 subjects, including 72 controls, have been studied. A semistructured interview was used to obtain informati on about delusions, hallucinations and other specific behavioral signs occu rring during the clinical course of the disease. We used the presence of de lusions or hallucinations as evidence of psychosis. The distribution of the 5-HT2A receptor gene genotypes and allele frequencies differs significantl y between AD patients with prominent psychiatric features compared to those patients without. We have observed the homozygosity for the C102 allele in 52 % of AD patients with psychotic symptoms as compared to 6.9% of patient s without psychosis. Our data strongly confirm previous studies suggesting that the genetic variation at this locus is associated with prominent psych otic features in AD and that the 102C allele could play an important role i n the clinical course of late onset AD.