Senior author John Cirrito, an assistant professor of neurology at Washington University School of Medicine in St. Louis, and colleagues at the University of Pennsylvania said amyloid beta is a protein produced by normal brain activity. However, these protein levels rise in the brains of patients with Alzheimer's causing them to clump together into plaques.
The study, published in Science Translational Medicine, found citalopram stopped the growth of plaques in mice and in young adults who were cognitively healthy, a single dose of the antidepressant lowered the production of amyloid beta -- the primary ingredient in plaques -- by 37 percent.
"Antidepressants appear to be significantly reducing amyloid beta production, and that's exciting," senior author John Cirrito, assistant professor of neurology at Washington University, said in a statement.
But while antidepressants generally are well tolerated, they have risks and side effects. Until we can more definitively prove that these drugs help slow or stop Alzheimer's in humans, the risks aren't worth it. There is still much more work to do."
The scientists said the findings were encouraging, but they cautioned it would be premature for people to take antidepressants solely to slow Alzheimer's disease.