Hydroxytryptamine transporter gene-linked polymorphic region (5HTTLPR) is associated with delusions in Alzheimer's disease.

More studies on wider samples of high selected demented patients are needed to confirm our results. However, the present findings suggested that a genetic factor related to serotonin metabolism might exert a protective role on the clinical expression of neuropsychiatric clusters in AD with important implications regarding mechanisms underlying delusions and their possible treatment across the AD and dementia spectrum.