Association of APOE genetic polymorphism with cognitive function and suicide history in geriatric depression

Apolipoprotein E (APOE) has been associated with a variety of late-life neuropsychiatric disorders, including geriatric depression. This study determined whether APOE genotypes affect vulnerability to geriatric depression. We also tested the effect of the presence of the APOE epsilon4 (APOE4) allele on age of onset, suicide attempt history and cognitive function in geriatric depressed patients. We genotyped APOE in 111 elderly inpatients diagnosed as having major depression and 144 normal controls. The depressed patients were evaluated at baseline using the Hamilton Rating Scale for Depression and the Mini-Mental State Examination (MMSE) after admission. Age of onset of depression and suicide attempt history in the depressed group were evaluated by interview and medical record. We found no association between APOE genotypes and geriatric depression (p = 0.342) or APOE4 status and age of onset of depression (p = 0.281). However, compared with depressed subjects lacking the APOE epsilon4 allele, depressed subjects who were also APOE4 carriers showed significantly lower MMSE scores (p = 0.021) and an increased suicide attempt history (p = 0.012). The APOE genotype may contribute to cognitive performance and suicidality in geriatric depression, rather than being a specific risk factor for the disorder.