A sleep disorder is a disruptive
pattern of sleep that may include difficulty falling or staying asleep, falling
asleep at inappropriate times, excessive total sleep time, or abnormal behaviors
associated with sleep.
More than 100 different disorders
of sleeping and waking have been identified. They can be grouped within 4 main
categories: problems with staying and falling asleep, problems with staying
awake, problems with adhering to a regular sleep schedule, and sleep disruptive