Hypersomnia

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Hypersomnia

Definition

Hypersomnia refers to a set of related disorders that involve excessive daytime sleepiness.

There are two main categories of hypersomnia: primary hypersomnia (sometimes called idiopathic hypersomnia) and recurrent hypersomnia (sometimes called recurrent primary hypersomnia). Both are characterized by the same signs and symptoms and differ only in the frequency and regularity with which the symptoms occur.

Primary hypersomnia is characterized by excessive daytime sleepiness over a long period of time. The symptoms are present all, or nearly all, of the time. Recurring hypersomnia involves periods of excessive daytime sleepiness that can last from one to many days and recur over the course of a year or more. The main difference between this and primary hypersomnia is that persons experiencing recurring hypersomnia will have prolonged periods where they do not exhibit any signs of hypersomnia, whereas persons experiencing primary hypersomnia are affected by it nearly all the time. One of the best documented forms of recurrent hypersomnia is Kleine-Levin syndrome , although there are other forms as well.

There are many different causes for daytime sleepiness that are not considered hypersomnia, and there are many diseases and disorders in which excessive daytime sleepiness is a primary or secondary symptom. Feelings of daytime sleepiness are often associated with the use of common substances such as caffeine, alcohol, and many medications. Other common factors that can lead to excessive daytime sleepiness that is not considered hypersomnia include shift work and insomnia. Shift work can disrupt the body’s natural sleep rhythms. Insomnia can cause excessive daytime sleepiness because of lack of nighttime sleep and is a separate disorder.

Causes and symptoms

People experiencing hypersomnia do not get abnormal amounts of nighttime sleep. However, they often have problems waking up in the morning and staying awake during the day. People with hypersomnia nap frequently and do not feel refreshed upon waking from the naps. Hypersomnia is sometimes misdiagnosed as narcolepsy. In many ways the two are similar. One significant difference is that people with narcolepsy experience a sudden onset of sleepiness, while people with hypersomnia experience increasing sleepiness over time. Also, people with narcolepsy find daytime sleep refreshing, while people with hypersomnia do not.

People with Kleine-Levin syndrome have symptoms that differ from the symptoms of other forms of hypersomnia. These people may sleep up to 20 or more hours a day in episodes that last for several weeks. In addition, they are often irritable, sometimes to the point of violence. They can be sexually uninhibited (hyper-sexual) and make indiscriminate sexual advances. There may be some confusion and memory deficits, as well. People with Kleine-Levin syndrome often eat uncontrollably and rapidly gain weight, unlike people with other forms of hypersomnia. This form of recurrent hypersomnia is very rare, with only 27 cases described in the scientific literature between 1962 and 2004. The disorder, which most often starts in adolescence, generally lessens and resolves as a person ages.

The causes of hypersomnia remain unclear. There is some speculation that in many cases it can be attributed to problems involving the hypothalamus, but evidence supporting this idea is sparse. In the case of Kleine-Levin, there is some suggestion that onset of the disorder may in some cases be linked to certain viral illnesses.

Demographics

Hypersomnia is an uncommon disorder. In general, no more than 5% of adults complain of excessive sleepiness during the daytime. That does not mean all those who complain of excessive sleepiness have hypersomnia. There are many other possible causes of daytime sleepiness. Of all the people who visit sleep clinics because they feel they are too sleepy during the day, only about 5-10% are diagnosed with primary hypersomnia. Kleine-Levin syndrome is present in about four times more males than females, but it is a very rare syndrome.

Hypersomnia generally appears when the patient is between 15 and 30 years old. It does not begin suddenly but becomes apparent slowly, sometimes over years.

KEY TERMS

Hypothalamus — A part of the forebrain that controls heartbeat, body temperature, thirst, hunger, blood pressure, blood-sugar levels, and other functions.

Narcolepsy — A disorder characterized by frequent and uncontrollable attacks of deep sleep.

Diagnosis

Hypersomnia is characterized by excessive daytime sleepiness, and daytime naps that do not result in a more refreshed or alert feeling. Hypersomnia does not include lack of nighttime sleep. People experiencing problems with nighttime sleep may have insomnia, a separate sleep disorder. In people with insomnia, excessive daytime sleepiness may be a side effect.

The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), which presents the guidelines used by the American Psychiatric Association for diagnosis of disorders, states that hypersomnia symptoms must be present for at least a month, and must interfere with a person’s normal activities. Also, the symptoms cannot be attributed to failure to get enough sleep at night or to another sleep disorder. The symptoms cannot be caused by another significant psychological disorder, nor can they be a side effect of a medicinal or illicit drug or a side effect of a general medical condition. For a diagnosis of recurrent hypersomnia, the symptoms must occur for at least three days at a time, and the symptoms have to be present for at least two years.

Treatments

There have been some attempts to use drugs for treating hypersomnia. No substantial body of evidence supports the effectiveness of these treatments. Stimulants are not generally recommended to treat hypersomnia because they treat the symptoms but do not address the cause. Some research suggests that treatments targeting the hypothalamus may be effective therapy for hypersomnia.

Prognosis

Kleine-Levin syndrome has been reported to occasionally resolve by itself around middle age. Except for that syndrome, hypersomnia is considered both a lifelong disorder and one that can be significantly disabling. There is no body of evidence that concludes there is a way to successfully treat the majority of hypersomnia cases.

Resources

BOOKS

Aldrich, Michael S. Sleep Medicines. New York: Oxford University Press, 1999.

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text rev. Washington, D.C.: American Psychiatric Association, 2000.

Chokroverty, Susan, ed. Sleep Disorders Medicine: Basic Science, Technical Considerations, and Clinical Aspects, 2nd ed. Boston: Butterworth-Heinemann, 1999.

Sadock, Benjamin J., and Virginia A. Sadock, eds. Comprehensive Textbook of Psychiatry, 7th ed., Vol. 2. Philadelphia: Lippincott Williams and Wilkins, 2000.

Thorpy, Michael J, ed. Handbook of Sleep Disorders. New York: Marcel Dekker, 1990.

PERIODICALS

Arnulf, I., J.M. Zeitzer, J. File, N. Farber, and E. Mignot. “Kleine-Levin Syndrome: A Systematic Review of 186 Cases in the Literature.” Brain 128 (2006): 2763–76.

Boris, Neil W., Owen R. Hagina, and Gregory P. Steiner. “Case Study: Hypersomnolence and Precocious Puberty in a Child with Pica and Chronic Lead Intoxication.” Journal of the American Academy of Child and Adolescent Psychiatry 35.8 (Aug. 1996): 1050–55.

Mahowald, Mark W., and Carlos H. Schenck. “Insights from Studying Human Sleep Disorders.” Nature 43 (2005): 1279–85.

National Center on Sleep Disorders Research Working Group, Bethesda, Maryland. “Recognizing Problem Sleepiness in Your People.” American Family Physician (Feb. 15, 1999): 937–38.

ORGANIZATIONS

American Academy of Sleep Medicine. 6301 Bandel Road NW, Suite 101, Rochester, MN 55901. Telephone: (507) 287-6006. Web site: <www.asda.org>.

National Organization for Rare Disorders (NORD). P.O. Box 1968/55 Kenosia Ave., Danbury, CT, 06813-1968. Telephone: (203) 744-0100. Web site: <http://www.rarediseases.org>