The pain and fatigue that people with chronic illness experience have a large impact on their daily lives, including sleep. Because of their illness, these patients often have trouble sleeping at night and are sleepy during the day. This is especially the case for people who have neurological (nervous system) diseases such as Parkinson’s and Alzheimer’s. Insomnia can make the person’s pain and quality of life worse. In addition, some drugs used to treat chronic illnesses can cause sleep problems.