The authors had gathered and examined data on a group of Medicare recipients in the USA who were 65 or over.
According to the researchers, studies have indicated that from 3% to 63% of patients with MCI have depressive symptoms. Other studies have demonstrated that people with a history of depression have a higher risk of dementia during their later years. A study published in Archives of Neurology in May 2011 revealed that mild cognitive impairment and dementia are much more common among very old women.
Experts are not sure what the mechanisms are between depression and cognitive decline. They believe several mechanisms are involved, the authors wrote as background information.
Edo Richard, M.D., Ph.D. and team gathered and analyzed data on 2,160 community-dwelling Medicare recipients. They were specifically looking out for a link between depression late in life and MCI.
Dr. Richard wrote:
"We found that depression was related to a higher risk of prevalent MCI and dementia, incident dementia, and progression from prevalent MCI to dementia, but not to incident MCI."
The researchers found that:
- Baseline depression was linked to prevalent MCI and dementia
- Baseline depression was linked to a greater risk of incident dementia, but not with incident cognitive impairment
- Those with MCI as well as depression at baseline had a greater risk of eventually developing dementia, particularly vascular depression. These patients did not have a higher risk of eventually developing Alzheimer's disease.
"The association of depression with prevalent MCI and with progression from MCI to dementia, but not with incident MCI, suggests that depression accompanies cognitive impairment but does not precede it."
Researchers from the Mayo Clinic found that apathy and depression are strongly linked to a person's risk of progressing from mild cognitive impairment to dementia, including Alzheimer's disease.
Written by Christian Nordqvist