Common genetic factors in depression and Alzheimer’s disease have been identified in a new study, with researchers finding that people with worse depression suffer from a more rapid decline in memory.
Now the researchers say the genes that are common to both conditions could be targeted to reduce the risk of people developing Alzheimer’s disease.
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The study’s co-senior author, Dr Aliza Wingo of Emory University School of Medicine in Atlanta, said: “It raises the possibility that there are genes that contribute to both illnesses. While the shared genetic basis is small, the findings suggest a potential causal role of depression on dementia.”
The team carried out a study of the entire genome to search for common areas linking particular conditions. They identified a number of brain proteins and transcripts – the messages that encode proteins – that were associated both with depression and Alzheimer’s disease.
Co-senior author Dr Thomas Wingo said: “This study reveals a relationship between depression and Alzheimer’s disease and related dementia at the genetic level. This is important because it may explain, at least in part, the well-established epidemiologic association between depression and higher risk for dementia.
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“This relationship raises the question of whether treatment of depression can mitigate the risk for dementia. We identified genes that may explain the relationship between depression and dementia here that merit further study. Such genes may be important treatment targets for both depression and reduction of dementia risk.”
The study has been published in Biological Psychiatry and editor Dr John Krystal said: “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.
“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.”
Read the study in Biological Psychiatry.
