At a Glance People who slept six hours or less per night in their 50s and 60s were more likely to develop dementia later in life. The findings suggest that inadequate sleep duration could increase dementia risk and emphasize the importance of good sleep habits. The study explored the links between sleep and dementia. tab1962 / iStock / Getty Images Plus Changes in sleep patterns are common in people with Alzheimer’s disease and other dementias. They may wake up often during the night and find it hard to get back to sleep. These sleep problems are thought to result from brain changes caused by the disease that affect the sleep-wake cycle.