PHILADELPHIA, Pa. — A new genetic study finds depression and Alzheimer’s disease shared similar genes. The findings show depression actually has a link to the onset of Alzheimer’s and having severe depression can accelerate memory decline.
While the results do not mean people with a brief episode of depression will eventually develop dementia, it does suggest that recurring depression, if left untreated, could quicken the onset of dementia-related symptoms.
Alzheimer’s is the most prevalent form of dementia. Worldwide, around 50 million live with some form of the memory-robbing disease. Meanwhile, the Anxiety and Depression Association of America estimates more than 16 million American adults deal with major depressive disorder.
“The costs of ineffectively treated depression continue to mount. There has been increasing evidence that major depressive disorder increases the risk for Alzheimer’s disease, but little insight into this relationship,” says John Krystal, MD, editor of the journal Biological Psychiatry, in a media release.
“This innovative study, which links genetic risk mechanisms to molecular changes in the brain, provides the clearest link to date supporting the hypothesis that depression plays a causal role in the biology of Alzheimer’s disease.”
The researchers scanned the genome of areas involved with chronic conditions and found 28 brain proteins and 75 transcripts — messages that encode proteins — linked to depression. Of these, 46 transcripts and seven proteins were shared genetic factors for Alzheimer’s.
“This study reveals a relationship between depression and Alzheimer’s disease and related dementia at the genetic level,” says Thomas Wingo, MD, co-senior author of the study. “This is important because it may explain, at least in part, the well-established epidemiologic association between depression and higher risk for dementia.”
The research is published in Biological Psychiatry.