Psychotic symptoms in Alzheimer's disease and 5-HTTLPR polymorphism of the serotonin transporter gene: Evidence for an association

Davide Quaranta, Alessandra Bizzarro, Camillo Marra, Maria Gabriella Vita, Davide Seripa, Alberto Pilotto, Valeria Sebastiani, Patrizia Mecocci, Carlo Masullo

Research output: Contribution to journalArticlepeer-review


The occurrence of psychotic symptoms is common in Alzheimer's disease (AD), configuring a possibly distinguished clinical entity defined "Psychosis in Alzheimer's Disease" (AD-P). In order to investigate demographic clinical and biological variables potentially associated to the occurrence of AD-P, 148 AD patients were selected. Mini-Mental State Examination (MMSE), Activities of Daily Living (ADL), and Instrumental Activities of Daily Living (IADL) scores, socio-economic status and 5-HTTLPR and APOE gene polymorphisms were determined for each subject. AD-P patients were significantly more frequent carriers of the long (L) allele of 5-HTTLPR. The percentage of AD-P increased with the number of copies of the L-allele: 13% among S homozygote; 36% among heterozygotes; 51% among L-homozygotes. No difference resulted between AD-P and non-psychotic AD (AD-NP) in the distribution of the ε4 allele of APOE. The risk of AD-P was increased in L/L homozygous (OR = 7.25, p = 0.003) and, to a lesser extent, in heterozygous (OR = 3.91; p = 0.018). Backward logistic regression analysis showed that the risk for AD-P was increased in older subjects (OR = 1.07; p = 0.018) while an increase of MMSE score was protective (OR = 0.90; p = 0.004). The occurrence of AD-P resulted significantly related to age at examination, cognitive status, and to the presence of the 5-HTTLPR L-allele.

Original languageEnglish
Pages (from-to)173-180
Number of pages8
JournalJournal of Alzheimer's Disease
Issue number1
Publication statusPublished - 2009


  • 5-HTT gene
  • 5-HTTLPR
  • Alzheimer's disease
  • APOE gene polymorphisms
  • Neuropsychiatric inventory
  • Psychotic symptomatology

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Geriatrics and Gerontology
  • Clinical Psychology


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