One of the most powerful predictors in neuropsychiatry is the epsilon 4 (ε4) allele of the apolipoprotein gene (APOE).

Individuals who carry this ε4 variant of APOE are at increased risk for developing Alzheimer’s disease, early age of Alzheimer’s disease onset, and more rapid progression of Alzheimer’s disease symptoms. APOE ε4 has also been associated with atherosclerosis as well as cardiovascular and cerebrovascular disease.

A new study published in the current issue of Biological Psychiatry suggests that even when controlling for the risk for Alzheimer’s disease, the APOE ε4 allele also conveys an increased risk for late-life depression.

In this study, researchers examined the relationship between APOE ε4 and depression in a large population-based sample of 839 older Swedish adults followed over 5 years.

“In our study, the presence of the APOE ε4 predicted future depression, even after excluding individuals who later developed dementia,” explained corresponding author Dr. Silke Kern at the University of Gothenburg. “It was also related to dementia. APOE ε4 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.”

Image of DNA.

“Late-life depression is an under-appreciated source of distress and disability in older people,” said Dr. John Krystal, Editor of Biological Psychiatry. “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.”

ABOUT THIS DEPRESSION AND GENETICS RESEARCH

Source: Elsevier
Image Source: The image is in the public domain
Original Research: Abstract for “A 9-Year Prospective Population-Based Study on the Association Between the APOE*E4 Allele and Late-Life Depression in Sweden” by Tziona Ben‐Gedalya, Lorna Moll, Michal Bejerano‐Sagie, Samuel Frere, Wayne A Cabral, Dinorah Friedmann‐Morvinski, Inna Slutsky, Tal Burstyn‐Cohen, Joan C Marini, and Ehud Cohen in Biological Psychiatry. Published online November 2015 doi:10.1016/j.biopsych.2015.01.006


Abstract

A 9-Year Prospective Population-Based Study on the Association Between the APOE*E4 Allele and Late-Life Depression in Sweden

Background
It is well established that there is an association between the apolipoprotein E (APOE) ε4 allele (APOE*E4) and Alzheimerʼs disease. It is less clear whether there is also an association with geriatric depression. We examined the relationship between APOE*E4 and 5-year incidence of depression in a Swedish population-based sample of older adults without dementia and excluding older adults who developed dementia within 4 years after the diagnosis of depression.

Methods
In 2000–2001, 839 women and men (age range, 70–92 years; mean age, 73.8 years) free from dementia and depression underwent neuropsychiatric and neuropsychological examinations and genotyping of the APOE*E4 allele. Follow-up evaluations were conducted in 2005 and 2009.The association between APOE*E4 allele and 5-year incidence of depression was examined, while avoiding possible confounding effects of clinical or preclinical dementia by excluding participants who had dementia at study entry, subsequently developed dementia during the 9-year follow-up period, or had a decline in Mini-Mental State Examination score of ≥5 points.

Results
Among subjects without depression at study entry and without dementia or significant cognitive decline during the subsequent 9 years, APOE*E4 was prospectively associated with more severe depressive symptoms (b = 1.56, p = .007), incident minor depression (odds ratio = 1.99 [confidence interval = 1.11–3.55], p = .020), and any depression (odds ratio = 1.75 [confidence interval = 1.01–3.03], p = .048).

Conclusions
The presence of the APOE*E4 allele predicted future depression in this Swedish population study, even after excluding depressed individuals who later developed dementia, suggesting that the APOE*E4 allele could potentially identify people at high risk for clinically significant depression.

“A 9-Year Prospective Population-Based Study on the Association Between the APOE*E4 Allele and Late-Life Depression in Sweden” by Tziona Ben‐Gedalya, Lorna Moll, Michal Bejerano‐Sagie, Samuel Frere, Wayne A Cabral, Dinorah Friedmann‐Morvinski, Inna Slutsky, Tal Burstyn‐Cohen, Joan C Marini, and Ehud Cohen in Biological Psychiatry. Published online November 2015 doi:10.1016/j.biopsych.2015.01.006