Depression Identified as a Risk Factor for Dementia

Depression in older adults may increase the risk of dementia and mild cognitive impairment, according to a recent study.

“These findings are exciting because they suggest depression truly is a risk factor for dementia, and if we can target and prevent or treat depression and causes of stress we may have the potential to help people maintain their thinking and memory abilities into old age,” said Robert S. Wilson, PhD, one of the study’s authors and researcher at Rush University Medical Center in Chicago.
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For the study, researchers studied 1764 people from the Religious Orders Study and the Rush Memory and Aging Project. The participants (mean age of 77) reported no cognitive problems at the start of the study.

Every year for an average of 8 years, participants were tested for thinking and memory skills, and screened for symptoms of depression (eg, lack of appetite and loneliness).

Over the course of the study, 680 people died; autopsies were performed on 582 of the deceased to examine damage from dementia in the brain.

Furthermore, 52% of participants manifested mild cognitive impairment, or mild problem with memory or thinking, during the study period. Note: These symptoms are precursors to Alzheimer’s disease.

A total of 315 participants developed dementia.

Researchers found no apparent association between brain damage and the level of depression symptoms or change in depression symptoms over time.

Individuals who developed mild cognitive impairment were more likely to have displayed higher levels of depression symptoms prior to diagnosis, but no more likely to have a change in symptoms after diagnosis than individuals without mild cognitive impairment.

Individuals with dementia were also more likely to have a higher level of depression prior to the onset of dementia, but reported more rapid decrease in depression after dementia developed.

The complete study is published in the July issue of Neurology.

-Michelle Canales

References:

Wilson RS, Capuano AW, Boyle PA, et al. Clinical-pathologic study of depressive symptoms and cognitive decline in old age. Neurology. 2014 July [epub ahead of print] doi: 10.1212/WNL.0000000000000715.

American Academy of Neurology. How is depression related to dementia? July 30, 2014. www.aan.com/PressRoom/Home/PressRelease/1299. Accessed July 31, 2014.