Sleep disorders include a variety of conditions related to sleep and daytime alertness. Sleep disorders commonly prevent people from getting enough sleep, cause unusual behaviors during sleep, or cause people to sleep during the wrong time of the day. Roughly 20-40 percent of all Americans suffer from some form of sleep disorder. Sleep disorders affect people of all ages, including children and even infants. Although some sleep disorders can be traced to correctable physical abnormalities, most stem from physical, neurological, or psychiatric causes that are more difficult to isolate.
Sleep disorders take a number of different forms exhibiting a great variety of symptoms.
They can be divided into disorders of excessive sleepiness, insomnias, disorders of the sleep-wake schedule and parasomnias. Excessive sleepiness can be caused by sleep disorders including insufficient sleep, sleep-related disordered breathing, narcolepsy, periodic leg movements and interruptions to sleep. Non-breathing episodes can last from 10 seconds to a few minutes each and can occur hundreds of times a night. Sleep apnea is most often caused by excessive relaxation of muscles in the patient's airway. When muscles relax and sag during sleep, the attempt to breathe can collapse the airway and obstruct breathing.