Here’s one of many recent studies showing low lack of good quality sleep can cause memory problems, dementia, and even Alzheimer’s disease. In this Johns Hopkins study, researchers found that people who slept less of had trouble sleeping had higher levels of beta amyloid plaques in their brain. Having plaques alone doesn’t mean you’ll develop Alzheimer’s disease, but what this study showed was that sleep may play an important role in how your brain rids itself of beta amyloid plaques, which are one of the hallmarks of dementia.