In a new study from The University of Texas, researchers found that middle-aged people with depressive symptoms who carry a genetic variation called apolipoprotein (APOE) ε4 may be more at risk to develop tau protein accumulations in the brain.
These persons are likely decades before any type of dementia diagnosis.
The research is based on depression assessments and positron emission tomography (PET) imaging conducted among 201 participants. The mean age of these participants was 53.
Amyloid beta (amyloid-β) and tau are proteins that aggregate in the brains of people with Alzheimer’s disease and also typically increase to a milder extent with normal aging.
The study found no associations of depressive symptoms and depression with amyloid-β. The only association was with tau, and only in APOE ε4 variant carriers.
About one-fourth of the participants (47 of 201) were ε4 carriers, by virtue of having at least one copy of the ε4 allele.
Having one copy of APOE ε4 increases the risk of developing Alzheimer’s by as much as two- to threefold, but some people with this variant live into their 80s and 90s and never develop the disease.
In the study, the depressive symptoms (and depression if symptoms were severe enough to reach that diagnostic threshold) were evaluated at the time of PET imaging, as well as eight years prior.
The team found links between depressive symptoms and increased tau in two brain regions linked to memory and emotion.
The team says more studies are needed to further understand what is happening, but it is intriguing to think about the clinical significance of our findings in terms of cognition as well as emotional regulation.
If you care about depression and your health, please read studies about this mood function is low or even absent in people with depression and findings of a new treatment could rapidly reduce depression symptoms.
For more information about depression prevention and treatment, please see recent studies about using depression drugs for a long time may cause addiction and results showing that stress, anxiety or depression? Treatment starts with the right diagnosis.
The study is published in The Journal of Alzheimer’s Disease. One author of the study is Mitzi M. Gonzales, Ph.D.
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