Prevalence of neuropsychiatric symptoms in mild cognitive impairment and normal cognitive aging: population-based study.
BACKGROUND
Little is known about the population-based prevalence of neuropsychiatric symptoms in mild cognitive impairment (MCI).


OBJECTIVE
To estimate the prevalence of neuropsychiatric symptoms in MCI and normal cognitive aging in a defined population.


METHODS
Cross-sectional study derived from an ongoing population-based prospective cohort study.


METHODS
The Mayo Clinic Study of Aging.


METHODS
We studied a random sample of 1969 individuals without dementia from the target population of 9965 elderly persons residing in Olmsted County (Minnesota) on the prevalence date (October 1, 2004). Neuropsychiatric data were available for 319 of 329 subjects with MCI (97.0%) and 1590 of 1640 subjects with normal cognition (97.0%). Neurologic, cognitive, and neuropsychiatric data were obtained from the study participants. A classification of MCI, dementia, and normal cognitive aging was adjudicated by an expert consensus panel. Accordingly, 329 subjects were classified as having MCI and the remaining 1640 subjects were classified as having normal cognition.


METHODS
Neuropsychiatric Inventory Questionnaire score.


RESULTS
Multivariate logistic regression analyses were conducted after adjusting for age, sex, and educational status. By considering both the odds ratio (OR) and the frequency of a symptom, the most distinguishing features between the 2 groups were apathy (OR, 4.53; 95% confidence interval [CI], 3.11-6.60; P < .001), agitation (3.60; 2.18-5.92; P < .001), anxiety (3.00; 2.01-4.48; P < .001), irritability 2.99; 2.11-4.22; P < .001), and depression (2.78; 2.06-3.76; P < .001). The OR was highest for delusion (8.12; 95% CI, 2.92-22.60; P < .001); however, it was rare in both subjects with MCI (11 of 319 [3.4%]) and those with normal cognition (6 of 1590 [0.4%]). Thus, the population attributable risk for delusion was only 2.62% compared with 14.60% for apathy.


CONCLUSIONS
Nonpsychotic symptoms affected approximately 50% of subjects with MCI and 25% of subjects with normal cognition. In contrast, psychotic symptoms were rare.
Department of Psychiatry and Psychology, College of Medicine, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA. geda.yonas@mayo.edu
Yonas E
YE
Geda
Rosebud O
RO
Roberts
David S
DS
Knopman
Ronald C
RC
Petersen
Teresa J H
TJ
Christianson
Vernon S
VS
Pankratz
Glenn E
GE
Smith
Bradley F
BF
Boeve
Robert J
RJ
Ivnik
Eric G
EG
Tangalos
Walter A
WA
Rocca
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008910:Minnesota; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011446:Prospective Studies; D011594:Psychometrics; D012016:Reference Values