Bad news for buzzkills: Researchers at King’s College London speculate that habitually ruminating on past mistakes or worrying about terrible things that might happen in the future can alter your brain—and potentially leave you susceptible to Alzheimer’s disease.


The researchers crafted this hypothesis after combing through hundreds of published studies on the topic.

Repetitive negative thinking puts your body in a state of stress, increases your release of the stress hormone cortisol, and activates certain regions of your brain that are implicated in Alzheimer’s disease, says study author Natalie Marchant, Ph.D.

Though negative thinking is common in depression and anxiety—both also associated with an increased risk for Alzheimer’s—Marchant says the thinking pattern may be the “active ingredient” in those conditions that elevates your odds. That means a bad mindset alone—without having depression or anxiety—could ultimately raise your risk for the memory-destroying disease.

There’s still a bunch of research that needs to be done. But if further studies support the theory, it could prompt investigation into whether breaking the pattern of negative repetitive thinking—such as through cognitive behavioral therapy or mindfulness-based meditation—could actually cut Alzheimer’s cases.