Overview

Hypersomnia, which refers to either excessive daytime sleepiness or excessive time spent sleeping, is a condition in which a person has trouble staying awake during the day. People who have hypersomnia can fall asleep at any time -- for instance, at work or while they are driving. They may also have other sleep-related problems, including 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.

Causes of 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 (sleep deprivation)
• Being overweight
• Drug or alcohol abuse
• A head injury or a neurological disease, such as multiple sclerosis or Parkinson's disease
• Prescription drugs, such as tranquilizers or antihistamines
• Genetics (having a relative with hypersomnia)
• Depression