For adults over 65, having depression and mild cognitive impairment (MCI) can leave the person vulnerable to accelerated brain aging, according to a new study. Meryl A. Butters, Ph.D., an associate professor of psychiatry at the University of Pittsburgh School of Medicine and senior investigator on the study, said that older adults with depression already have double the chance of developing dementia, compared to those who have never been diagnosed with depression.
“Better understanding of the neurobiology of cognitive impairment in depression can provide new targets for developing more specific treatments, not only for its prevention and treatment, but also for its downstream negative outcomes, including the development of dementia and related disorders,” said Butters.
For the study, researchers collected blood samples from 80 adults in remission after being treated for major depression, 36 had MCI and 44 had normal cognitive function. After scanning the blood samples for 242 proteins involved in biologic pathways, the researchers performed PET and MRI brain scans on the participants. The results showed that the participants with MCI showed “differences in the biologic activity of 24 proteins that are involved in the regulation of immune and inflammatory pathways, intracellular signaling, cell survival, and protein and lipid balance.” In addition, those with MCI also showed a greater tendency for small strokes, but showed no difference in the amount of beta-amyloid deposition, a protein associated with Alzheimer’s.
“If you take these results altogether, they suggest that people with depression and cognitive impairment may be more vulnerable to accelerated brain aging, which in turn puts them at risk for developing dementia,” Butters said. “Ultimately, if we can understand what happens in the brain when people are depressed and suffer cognitive impairment, we can then develop strategies to slow or perhaps stop the impairment from progressing to dementia.”