Four components describe behavioral symptoms in 1,120 individuals with late-onset Alzheimer's disease.
OBJECTIVE
To investigate behavioral components of Alzheimer's disease (AD) and to analyze behavioral components in relation to disease severity, apolipoprotein E genotype (APOE), sex, years of education, age at onset, and cognitive impairment.


METHODS
Cross-sectional study.


METHODS
Data were collected from community-dwelling individuals and those residing in nursing homes.


METHODS
A total of 1,120 individuals meeting National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association criteria for late-onset probable AD.


METHODS
Behavioral symptoms were assessed using the Neuropsychiatric Inventory. First-order polychoric correlations, controlling for disease severity, between the 12 symptom domain scores were estimated, and the resulting matrix underwent principal components analysis.


RESULTS
Four interpretable components were identified: behavioral dyscontrol (euphoria, disinhibition, aberrant motor behavior, and sleep and appetite disturbances), psychosis (delusions and hallucinations), mood (depression, anxiety, and apathy), and agitation (aggression and irritability). Scores on the four components were associated with severity of cognitive impairment. Higher behavioral dysfunction, agitation, and mood component scores were associated with lower age at onset. Behavioral dysfunction and mood component scores were associated with sex. None of the components were associated with age at assessment, years of education, or number of APOE epsilon4 alleles.


CONCLUSIONS
Four behavioral components were identified that were comparable with those observed previously. Future analysis of these components will strengthen understanding of the underlying pathology of behavioral symptoms and AD.
Hollingworth
Paul
P
Department of Psychological Medicine, Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom.
Hamshere
Marian L
ML
Moskvina
Valentina
V
Dowzell
Kimberley
K
Moore
Pamela J
PJ
Foy
Catherine
C
Archer
Nicola
N
Lynch
Aoibhinn
A
Lovestone
Simon
S
Brayne
Carol
C
Rubinsztein
David C
DC
Lawlor
Brian
B
Gill
Mike
M
Owen
Michael J
MJ
Williams
Julie
J
D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000453:epidemiology / Q000235:genetics / Q000523:psychology*; D001057:Apolipoproteins E / Q000235:genetics; D001526:Behavioral Symptoms / Q000175:diagnosis / Q000209:etiology*; D003072:Cognition Disorders / Q000209:etiology; D003430:Cross-Sectional Studies; D004522:Educational Status; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012720:Severity of Illness Index; D012737:Sex Factors
D001057:Apolipoproteins E