Increased familial risk of the psychotic phenotype of Alzheimer disease.
BACKGROUND
Psychotic symptoms in patients with AD (AD with psychosis [AD+P]) define a phenotype characterized by more rapid cognitive and functional decline and a liability to aggressive behaviors.


OBJECTIVE
To determine if AD+P aggregates within families.


METHODS
Case-control study of AD+P frequency in 461 siblings of 371 probands diagnosed with AD. All siblings were ascertained as part of a genetic investigation and also were diagnosed with AD. Statistical analysis used Generalized Estimating Equations to adjust for clustering within families.


RESULTS
AD+P in probands was associated with a significantly increased risk for AD+P in family members (OR, 2.41; 95% CI 1.46-4.0; p = 0.0006). The correlation among siblings for AD+P status was modest: 0.16.


CONCLUSIONS
AD+P demonstrates familial aggregation. Further studies are required to investigate a possible genetic basis of AD+P.
Sweet
R A
RA
Division of Geriatrics and Neuropsychiatry, School of Medicine, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA. SweetRA@MSX.UPMC.EDU
Nimgaonkar
V L
VL
Devlin
B
B
Lopez
O L
OL
DeKosky
S T
ST
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000235:genetics* / Q000523:psychology; D016022:Case-Control Studies; D015331:Cohort Studies; D016001:Confidence Intervals; D003702:Delusions / Q000235:genetics / Q000523:psychology; D005260:Female; D006212:Hallucinations / Q000235:genetics / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009679:Nuclear Family / Q000523:psychology; D016017:Odds Ratio; D010641:Phenotype; D011618:Psychotic Disorders / Q000235:genetics* / Q000523:psychology; D012307:Risk Factors