A depressive endophenotype of poorer cognition among cognitively healthy community-dwelling adults: results from the Western Australia memory study.
OBJECTIVE
The objective was to evaluate in a cognitively normal population the utility of an endophenotype of the depression-cognition link previously shown to be related to cognitive functioning in mild cognitive impairment and Alzheimer's disease.


METHODS
The data of 460 cognitively normal adults aged 32-92 years (M = 63.5, standard deviation = 9.24) from the Western Australian Memory Study with the Cross-national comparisons of the Cambridge Cognitive Examination-revised (CAMCOG-R) scores and 30-item Geriatric Depression Scale (GDS) scores were analyzed to determine the relationship between the five-item depressive endophenotype (DepE) scale drawn from the GDS and level of performance on a measure of cognitive functioning.


RESULTS
For the entire sample, there was a nonsignificant trend toward a negative relationship between DepE and CAMCOG-R scores. When analyzed for those 65 years and older, there was a significant negative relationship between the two measures (p = 0.001) with DepE scores significantly increasing the risk for performing more poorly on the CAMCOG-R (odds ratio = 1.53). Analysis of data for those 70 years and older showed that DepE was the only predictor significantly related to poorer CAMCOG-R performance (p = 0.001). For the 70 years and older group, DepE scores significantly increased the risk of poorer CAMCOG-R scores (odds ratio = 2.23). Analysis of the entire sample on the basis of ApoEε4 carrier status revealed that DepE scores were significantly negatively related only to ApoEε4 noncarrier regardless of age.


CONCLUSIONS
Elevated DepE scores are associated with poor neuropsychological performance among cognitively normal older adults. Use of the DepE may allow for the identification of a subset of older adults where depression is a primary factor in cognitive decline and who may benefit from antidepressant therapies.
Institute for Aging and Alzheimer's Disease Research, University of North Texas Health Science Center, Fort Worth, TX, USA.|Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA.
Leigh A
LA
Johnson
The School of Medical Sciences, Edith Cowan University, Joondalup, WA, Australia.|The McCusker Alzheimer's Research Foundation, Hollywood Private Hospital, Nedlands, WA, Australia.|The Centre of Excellence for Alzheimer's Disease Research and Care, Edith Cowan University, Joondalup, WA, Australia.
Hamid R
HR
Sohrabi
Institute for Aging and Alzheimer's Disease Research, University of North Texas Health Science Center, Fort Worth, TX, USA.|Department of Psychiatry, University of North Texas Health Science Center, Fort Worth, TX, USA.
James R
JR
Hall
The School of Medical Sciences, Edith Cowan University, Joondalup, WA, Australia.|The McCusker Alzheimer's Research Foundation, Hollywood Private Hospital, Nedlands, WA, Australia.|The Centre of Excellence for Alzheimer's Disease Research and Care, Edith Cowan University, Joondalup, WA, Australia.
Taddei
T
Kevin
Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA.
Melissa
M
Edwards
Institute for Aging and Alzheimer's Disease Research, University of North Texas Health Science Center, Fort Worth, TX, USA.|Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA.
Sid E
SE
O'Bryant
The School of Medical Sciences, Edith Cowan University, Joondalup, WA, Australia.|The McCusker Alzheimer's Research Foundation, Hollywood Private Hospital, Nedlands, WA, Australia.|The Centre of Excellence for Alzheimer's Disease Research and Care, Edith Cowan University, Joondalup, WA, Australia.
Ralph N
RN
Martins
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001057:Apolipoproteins E / Q000235:genetics; D060825:Cognitive Dysfunction / Q000175:diagnosis* / Q000235:genetics / Q000523:psychology; D003866:Depressive Disorder / Q000150:complications* / Q000523:psychology; D058068:Endophenotypes; D005260:Female; D005852:Geriatric Psychiatry; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D014904:Western Australia
D001057:Apolipoproteins E
cognition; depression; elders; endophenotype