Excessive Sleepiness and Narcolepsy

As many as 15 to 20 percent of adults report usually feeling sleepy during the day, and around 5 percent of the population experiences problems with daytime sleepiness.


Daytime sleepiness can include difficulty staying awake and/or tending to fall asleep unintentionally, particularly in monotonous situations, such as sitting in meetings, watching TV or driving. Excessive sleepiness can also be accompanied by the perception of sleeping too much at night. Sleepiness can result from many conditions, including insufficient sleep, neurological and medical conditions, medications and mood disorders such as depression.


Sleepiness is also linked to a range of sleep disorders, including narcolepsy. Narcolepsy affects up to 1 in 2,000 individuals in the United States. It is typically marked by a strong, sometimes irresistible urge to sleep at multiple points throughout the day. Effectively treating excessive sleepiness requires careful evaluation to determine the underlying cause.


Other symptoms of narcolepsy include:

  • Cataplexy is a sudden, brief, temporary loss of muscle control. It may involve the whole body collapsing to the floor. It more typically involves just specific muscles, like drooping of the head or arm or weakness of the knees. Cataplexy is most often triggered by a strong positive emotion, such as laughter or surprise.
  • Sleep paralysis is a feeling of not being able to talk or move for a brief period either when falling asleep or just after waking up. Touching the person usually causes the paralysis to disappear. Although it usually just ends on its own.
  • Hypnagogic hallucinations are vivid, dream-like experiences that are difficult to distinguish from reality, occurring when falling asleep or just after waking up. The hallucinations may involve images that are seen, heard or felt.

Additional Information on Excessive Sleepiness and Narcolepsy