Gene Associated with Alzheimer's Disease Separately Predicts Late Life Depression

Having a gene associated with Alzheimer’s may also mean a higher risk for depression.

The epsilon 4 allele of the apolipoprotein gene (APOE) is well known to be associated with the risk for Alzheimer’s disease, and in particular, earlier onset and more rapid progression of the disease. Whether the allele is independently associated with depression, is less clear.

Now a new study shows the allele is in fact a powerful predictor of later-life depression.

Researchers at the University of Gothenburg in Sweden followed 839 older women and men for nine years. The group members all had testing for dementia and depression at baseline and at five-year intervals. All were initially determined to be free of both. They also underwent genotyping for the APOE*E4 allele.

"In our study, the presence of the APOE epsilon 4 predicted future depression, even after excluding individuals who later developed dementia," said Silke Kern, senior researcher in Neuropsychiatric Epidemiology at the University of Gothenburg in Gothenburg, Sweden, and corresponding author of the study. "APOE epsilon 4 might be a marker for identifying older persons at risk to develop depression or dementia, which could be important for prevention and early detection of these common disorders."

"Late-life depression is an under-appreciated source of distress and disability in older people," said John Krystal, editor of Biological Psychiatry in a news release "The current study suggests a new link to the biology of Alzheimer's disease, even among people who do not show signs of memory impairment."

The study appeared in the November 15 issue of Biological Psychiatry.