hypersomnia

noun

hy·​per·​som·​nia ˌhī-pər-ˈsäm-nē-ə 

: a disorder of sleep that is characterized by prolonged nocturnal sleep periods which typically occur at least three times a week, by sleep that is not restorative or refreshing, and by the presence of excessive daytime sleepiness

Note: Hypersomnia may occur secondary to a medical condition (such as sleep apnea or depression) or the use of certain medications or may arise spontaneously from an unknown cause.

The International Classification of Sleep Disorders defines idiopathic hypersomnia as a disorder of excessive sleepiness that is associated with major sleep episodes, the cause of which is presumed to lie in the central nervous system.

—Sudhansu Chokroverty

also : excessive daytime sleepiness not associated with disturbed nocturnal sleep : hypersomnolence

Psychology Today reports that people who persistently fall asleep at their desks may be suffering from the dread hypersomnia …

—Curt Suplee

Examples of hypersomnia in a Sentence

Recent Examples on the Web

Dental appliances may help, too.5 Problems Staying Awake A healthcare provider may prescribe medications that treat hypersomnia symptoms. —Mara Betsch, Health, 10 June 2023

Two drugs will be compared to a placebo in a trial for excessive daytime sleepiness (hypersomnia). —Fran Kritz, Verywell Health, 22 Aug. 2023

One trial will focus on hypersomnia, or excessive sleep, while another will focus on problems falling or staying asleep. —Adrianna Rodriguez, USA TODAY, 31 July 2023

People with hypersomnia may want to nap at inappropriate times, like during work or meals. —Mara Betsch, Health, 10 June 2023

By now, Anna’s hypersomnia was threatening her livelihood. —David Rye, Discover Magazine, 7 Apr. 2014

Hypersomnia: With hypersomnia, staying awake during the day may be hard. —Sarah Klein, Health, 13 Mar. 2023

Anna’s case drove us to examine CSF from patients with other forms of hypersomnia. —David Rye, Discover Magazine, 7 Apr. 2014

The generic name for Anna’s persistent sleepiness, which no amount of sleep could erase, is hypersomnia. —David Rye, Discover Magazine, 7 Apr. 2014

Word History

First Known Use

1863, in the meaning defined above

Medical Definition

hypersomnia

noun

hy·​per·​som·​nia -ˈsäm-nē-ə 

1

: sleep of excessive depth or duration

2

: a disorder of sleep that is characterized by prolonged nocturnal sleep periods which typically occur at least three times a week, by sleep that is not restorative or refreshing, and by the presence of excessive daytime sleepiness

The International Classification of Sleep Disorders defines idiopathic hypersomnia as a disorder of excessive sleepiness that is associated with major sleep episodes, the cause of which is presumed to lie in the central nervous system.

—Sudhansu Chokroverty

also : excessive daytime sleepiness not associated with disturbed nocturnal sleep : hypersomnolence