The strong and robust positive association that was noted between the C allele of HTR2A and psychosis suggests that the HTR2A T102C polymorphism is a significant risk factor for psychosis of AD.
No significant differences in the distribution of allele and genotype frequencies of the 5-HTTLPR (p>0.01) and 5-HT2A T102C (p>0.05) were found between patients and controls as well as between the patients' subgroups without and with psychosis.
Subjects with possible or probable AD or mild cognitive impairment (MCI) without psychosis at study entry were genotyped for the HTR2A T102C polymorphism and reassessed every 6 months until psychosis onset.
Most replicated data suggest C allele of the 102 T/C and Tyr452 variants as risk factor for psychosis and antipsychotic response, but the number of not replicating studies does not allow to draw any definite conclusion.