Individual sleep requirements vary: Many people are long sleepers and require 9 to 10 hours of sleep a night, many are short sleepers.
Four major symptoms characterize most sleep disorders
Insomnia, hypersomnia, parasomnia and sleep-wake schedule disturbance. The symptoms often overlap.
INSOMNIA is difficulty in initiating or maintaining sleep. A brief period of insomnia is most often associated with anxiety, such as an examination or an impending job interview. In some people it is related to grief, loss, or almost any life change or stress.
HYPERSOMNIA manifests as excessive amounts of sleep, excessive daytime sleepiness, or sometimes both.
PARASOMNIA is an unusual or undesirable phenomenon that appear suddenly during sleep or that occurs at the threshold between waking and sleeping.
SLEEP-WAKE SCHEDULE DISTUEBANCE involves the displacement of sleep from its desired period. Patients cannot sleep when they wish to sleep; although they are able to sleep at other time.