Association analysis of apolipoprotein E genotype and risk of depressive symptoms in Alzheimer's disease

Objectives: Behavioural and psychological symptoms of dementia (BPSD) are potent predictors of carer distress and admission to institutional care. In Alzheimer's disease ( AD), depressive symptoms are one of the most common complaints affecting around 50% of all patients. There is speculation these symptoms result from known genetic risk factors for AD, therefore we investigated the role of apolipoprotein E epsilon4 in the aetiology of depression in AD. Methods: In this well-characterised cohort (n = 404) from the relatively genetically homogeneous Northern Ireland population, we tested the hypothesis that genetic variants of apolipoprotein E influence the risk for depressive symptoms in AD patients using the Neuropsychiatric Inventory (NPI-D) to determine the presence of depressive symptoms during the dementing illness. Results: A total of 55% of patients exhibited a history of depression/dysphoria during the course of the illness as gathered by the NPI-D questionnaire. Forty-six percent were suffering from depression/ dysphoria when the analysis was restricted to the month prior to interview. No statistically significant association between genotypes or alleles of apolipoprotein E and depression/ dysphoria in AD was observed, nor was any association noted between the presence of severe symptoms and genotypes/ alleles of apolipoprotein E. Conclusions: These results suggest apolipoprotein E genotype creates no additional risk for depressive symptoms in AD. Copyright (C) 2005 S. Karger AG, Basel.