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Depression May Increase Risk of Alzheimer’s Disease

People with memory problems who are depressed are more likely to develop Alzheimer’s disease compared with people who are not depressed, according to a study published in Neurology. However, the research also shows that the popular Alzheimer’s drug donepezil may delay the progression to Alzheimer’s disease for depressed people with mild cognitive impairment (MCI) or memory problems.
 
For the study, researchers followed 756 people with MCI who were aged 55 to 91 for three years. Of those, 208 were diagnosed with depression using a test that measures the severity and intensity of a person’s depressive symptoms. For every one point increase on the test, a participant’s risk of developing Alzheimer’s disease went up by 3%.
 
“Our longer term findings add to the body of evidence that suggests depression is a major risk factor for Alzheimer’s disease,” says study author Po H. Lu, PsyD, an assistant professor of neurology with the David Geffen School of Medicine at UCLA in Los Angeles. “Since the drug donepezil has been shown to improve the behavioral symptoms of Alzheimer’s disease, our study also tested whether the drug would delay the progression to Alzheimer’s disease in people with memory problems.”
 
Participants were given either vitamin E, donepezil, or a placebo pill. The study found that at 1.7 years, among depressed people with MCI, 11% of those taking donepezil developed Alzheimer’s disease compared with 25% of those who took vitamin E or placebo. At 2.2 years, 14% of those taking donepezil developed Alzheimer’s compared with 29% of those who took vitamin E or placebo. Donepezil had little effect in the group of people who were not depressed.
 
“If we can delay the progression of this disease for even two years, it could significantly improve the quality of life for many people dealing with memory loss,” says Lu.
 
— Source: American Academy of Neurology