The serotonin receptor gene (5-HT2A) has been reported to be a susceptible factor in behavioral and psychological symptoms of dementia (BPSD) in Alzheimer's disease (AD).
This study suggests a mechanism for the generation of different neuropsychiatric symptoms in AD from a single nucleotide polymorphism with reduced receptor binding in T102C5-HT2A receptor gene homozygotes correlating with susceptibility to depressive symptoms, whereas the relative preservation of receptor binding in heterozygotes with AD correlating with susceptibility to hallucinations.
Neuropsychiatric symptoms have been associated with polymorphisms of the promoter region (5-HTTPR ) and intron 2 of the serotonin transporter gene (5-HTTVNTR) or the 5-HT2A and 5-HT2C receptor genes in some but not all studies.