Neuropsychiatric symptom clusters and functional disability in cognitively-impaired-not-demented individuals.
OBJECTIVE
Previous research has shown that cognitively-impaired-not-demented (CIND) individuals with at least one neuropsychiatric symptom (NPS) have more functional disability than individuals without any NPSs. The objectives of the present study were to determine whether there are consistent clusters of NPS in CIND individuals and whether certain NPS clusters are more strongly associated with measures of functional disability than other NPS clusters in this population.


METHODS
This was a cross-sectional baseline study of NPS using the Neuropsychiatric Inventory (NPI) in a national clinic-based observational cohort study (the Canadian Cohort Study of Cognitive Impairment and Related Dementias study). The present investigation focuses on a subset of CIND subjects (73%) whose informant endorsed the presence of at least one NPI item.


RESULTS
A hierarchical cluster analysis identified two NPS clusters. One consisted of mood factors (i.e., depression, anxiety, apathy, irritability, and problems with sleep) and the other cluster captured frontal symptoms (i.e., aberrant motor behavior, disinhibition, agitation, and problems with appetite). NPSs grouped within the mood cluster were more common than the frontal cluster (95% of subjects had at least one NPS within the mood cluster versus 53% in the frontal cluster). However, the frontal cluster was more strongly associated with functional disability measures even after controlling for cognitive status (i.e., the Mini-Mental State Exam) and the mood cluster score.


CONCLUSIONS
The frontal cluster of NPSs was more strongly associated with functional disability than the mood cluster.
Peters
Kevin R
KR
Department of Psychology, Trent University, Peterborough, Ontario, Canada.
Rockwood
Kenneth
K
Black
Sandra E
SE
Hogan
David B
DB
Gauthier
Serge G
SG
Loy-English
Inge
I
Hsiung
Ging-Yuek R
GY
Jacova
Claudia
C
Kertesz
Andrew
A
Feldman
Howard H
HH
D000367:Age Factors; D000368:Aged; D016000:Cluster Analysis; D003072:Cognition Disorders / Q000175:diagnosis* / Q000503:physiopathology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003704:Dementia / Q000175:diagnosis; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis*; D019964:Mood Disorders / Q000175:diagnosis; D010555:Personality Inventory / Q000706:statistics & numerical data; D011379:Prognosis; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data