U. PITTSBURGH (US) — Depressed older adults with mild cognitive impairment showed improvements in language, memory, and executive functioning when they were treated with the dementia medication donepezil.
“Cognitive impairment is a core feature of depression in older adults and may foreshadow the development of dementia,” says Charles Reynolds, the study’s lead author and a professor of geriatric psychiatry at the University of Pittsburgh. “While treatment of depression usually benefits associated cognitive impairment, it does not completely regulate cognitive impairment and may not delay the progression to dementia.
“So, even in remission, older adults with past depression may still show residual cognitive difficulties, such as slowing of information processing speed and impairments in executive or language function. Our study showed that by adding donepezil, cognition can be improved beyond that which is seen simply with the treatment of depression itself.”
For the study—which is published in the current issue of the Archives of General Psychiatry—researchers compared 130 depressed adults over the age of 65, with 67 receiving donepezil, marketed under the trade name Aricept and 63 receiving a placebo.
The participants were followed for two years while researchers explored the effects of donepezil and placebo on five areas of neuropsychological functioning, including speed of information processing, memory, language, visuospatial functioning, and executive functioning, or brain processes that are responsible for planning and abstract thinking.
The researchers noted two unexpected findings: Donepezil seemed to delay the progression of mild cognitive impairment to frank dementia, and the use of the drug was associated with somewhat higher recurrence rates of clinical depression episodes, says Reynolds.
“So, there was both a benefit and a risk to adding donepezil to antidepressant pharmacotherapy in older adults. Fortunately, the majority of recurrent depressive episodes could be treated to remission.”
Adding donepezil to maintenance antidepressant medication appears to be useful to the care of older, depressed patients with mild cognitive impairment but does not benefit those with normal cognition. The researchers stress that clinicians should watch for early signs of any depressive relapse and treat as needed.
Researchers from the University of Toronto, Washington University in St. Louis, University of North Carolina at Chapel Hill, and the University of Virginia contributed to the study, which was supported in part by the National Institutes of Health.
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