Sleep Disorders Health Center
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Sleep Disorders: What Is Hypersomnia?
Hypersomnia is a condition marked by excessive daytime sleepiness. People who have hypersomnia can fall asleep at any time; for instance, at work or while driving. They may also have a lack of energy and trouble thinking clearly.
According to the National Sleep Foundation, up to 40% of people have some symptoms of hypersomnia from time to time.
What Causes Hypersomnia?
There are several potential causes of hypersomnia, including:
- The sleep disorders narcolepsy (daytime sleepiness) and sleep apnea (interruptions of breathing during sleep)
- Not getting enough sleep at night
- Being overweight
- Drug or alcohol abuse
- A head injury or a neurological disease, such as multiple sclerosis
- Prescription drugs, such as tranquilizers
- Genetics (having a relative with hypersomnia)
Reviewed by The Sleep
Medicine Center at The Cleveland Clinic.
WebMD Medical Reference provided in collaboration with the Cleveland Clinic![]()
Edited by
Leonard J. Sonne, MD on January 01, 2007
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