A depressive endophenotype of poorer cognition among cognitively healthy community-dwelling adults: results from the Western Australia memory study

ObjectiveThe 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. MethodsThe data of 460 cognitively normal adults aged 32-92years (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. ResultsFor the entire sample, there was a nonsignificant trend toward a negative relationship between DepE and CAMCOG-R scores. When analyzed for those 65years 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 70years and older showed that DepE was the only predictor significantly related to poorer CAMCOG-R performance (p=0.001). For the 70years 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 ApoE epsilon 4 carrier status revealed that DepE scores were significantly negatively related only to ApoE epsilon 4 noncarrier regardless of age. ConclusionsElevated 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. Copyright (c) 2014 John Wiley & Sons, Ltd.