According to experts at the University of California, San Francisco, older women with memory problems tend to have more difficulty sleeping than those without. The study followed 2,500 women, average age 69, with no memory problems around the start of the study, for 15 years. When they were assessed for sleeping problems at the end of the study, those with signs of severe mental decline were revealed to have nearly twice as much difficulty staying asleep and one and a half times difficulty falling asleep for longer than 90 minutes. Also, women with memory decline tended to nap more than two hours during the day. Scientists believe that memory loss increases the risk of sleep disturbance because there is a common underlying cause; in fact, brain changes that are revealed during Alzheimer’s disease and other memory-related dementias could increase both memory loss and sleep problems. Also, women with memory loss may experience anxiety and depression in greater numbers, which could affect their sleep patterns.