Disorder Information Sheet Mental Health Information from PsychNet-UK
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Hypersomnia is excessive sleepiness. It is an excessively deep or prolonged major sleep period. It may be associated with difficulty in awakening. It is believed to be caused by the central nervous system and can be associated with a normal or prolonged major sleep episode and excessive sleepiness consisting of prolonged (1-2 hours) sleep episodes of non-REM sleep and is characterized by:

Long sleep periods.

Excessive sleepiness or excessively deep sleep.

The onset is insidious (gradually, so you are not aware of it at first).

Typically appears before age 25.

Has been present for at lest six months.

A person with hypersomnia may sleep up to twelve hours a night, and still need frequent daytime naps. If the condition is diagnosed as recurrent hypersomnia, this is also called Kleine-Levin Syndrome.

Idiopathic hypersomnia is much like narcolepsy, except there is no cataplexy, no sleep paralysis, and no rapid eye movement when the victim first falls asleep.

Hypersomnia is one of the symptoms of major depression. In fact, people who are suffering from clinical depression may suffer from either insomnia (inability to fall asleep) or hypersomnia (excessive sleep) nearly every day. Bi-polar patients may also experience hypersomnia during depressive periods.

In between the symptomatic periods, the patients have normal sleep requirements and do not have excessive daytime sleepiness. Some patients may develop symptoms of irritability, impulsive behavior, depersonalization, hallucinations, depression, and confusion.

Associated Features:

Headaches, which may be Migrainous in quality.
Fainting Episodes
Hypnagogic Hallucinations and Sleep Paralysis may be encountered occasionally.

Differential Diagnosis: 

Some disorders have similar symptoms. The clinician, therefore, in his diagnostic attempt , has to differentiate against the following disorders which need to be ruled out to establish a precise diagnosis.

Sleep Apnea


Primary hypersomnia is an idiopathic disorder and it's etiology is not known. Although head injury or viral infections can cause a disorder resembling primary hypersomnia.. No genetic, environmental, or other predisposition has been identified.


Since the cause is still unknown, treatment consists of behavioral changes, good sleep hygiene and taking stimulants to help you be more alert. Limit your naps to one (preferably in the afternoon) lasting no longer than 45 minutes. Get at least 81/2 hours of sleep. Avoid shiftwork, alcohol and caffeine.

Counseling and Psychotherapy [ See Therapy Section ]:

Cognitive Behavioral Therapy to assist the patient adopt behavioral change strategies.

Pharmacotherapy [ See Psychopharmacology Section ] :

related books
  Narcolepsy and Hypersomnia
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Page Updated
20th July 2003