Antidepressants show promise in preventing Alzheimer’s

About five million Americans already have Alzheimer’s, and many more are expected to develop the disease in the next decades — unless scientists find a way to prevent it.

Taking a step toward that goal is one University of Pennsylvania researcher, who has found that common antidepressants may be useful not only in boosting mood, but also in warding off dementia. 

In the latest study, published today in the journal Science Translational Medicine, lead author and University of Pennsylvania psychiatrist Yvette Sheline said the group tested a type of antidepressant known as a selective serotonin reuptake inhibitor, or SSRI, to see how well it could prevent Alzheimer’s-related amyloid beta plaques in the brains of mice genetically programmed to develop the disease.

“In the mice that were exposed to the SSRI, the plaques basically stopped growing, and there were no new plaques that developed,” Sheline said. In contrast, the mice receiving the placebo had a substantial growth in plaques.

The researchers also found that in healthy young people, the drug lowered the amount of amyloid in their cerebrospinal fluid by 37 percent. That’s not the same as preventing plaques in people, but Sheline said higher concentrations of amyloid have been linked to plaque formation, so this is a promising finding.

“We know that amyloid builds up for a long time before people actually start to get cognitive changes,” she said. “So there’s a window of opportunity where if we can slow the progression of amyloid we may be able to slow the progression toward dementia.”

Sheline said it is too early to recommend using antidepressants in an “off-label” way to ward off  dementia, especially because there are side effects, such as nausea and vomiting. And the drug appears only to slow or prevent plaques instead of shrinking existing ones, indicating it would be more of a prophylactic than treatment for those already experiencing symptoms. But the researchers are planning their next step to see if the drug can limit the amount of amyloid in older people, which they hope will also translate into fewer plaques and delayed disease.