The link between depression and dementia has been noted by researchers and clinicians for several years now. After all, it seems obvious that one would suffer from feelings of depression as one gets older and experiences the earliest stages of cognitive decline. But a growing body of evidence is building to suggest we may have got the causal direction wrong when considering the associations between depression and dementia.
A new study led by Harvard Medical School researchers at Massachusetts General Hospital has found levels of amyloid beta plaques in the brain, the primary pathological characteristic of Alzheimer’s disease, can be directly correlated with both increasing symptoms of depression, and worsening cognition. The hypothesis is that depression and dementia can be symptoms of Alzheimer’s, with mild depression being possibly one of the first clinical signs of the neurodegenerative disease.
“Our research found that even modest levels of brain amyloid deposition can impact the relationship between depression symptoms and cognitive abilities,” says lead author on the study, Jennifer Gatchel.
The new research utilized data from the long-running Harvard Aging Brain Study, providing valuable longitudinal data tracking healthy adults at the earliest stages of cognitive decline. In this instance, data was analyzed from 276 older adults. All the subjects were cognitively unimpaired at the beginning of the study, and suffered from no more than mild depression.