Hypersomnia
Hypersomnia is a medical condition which is characterized by unusual sleepiness. People with hypersomnia easily feel sleepy during the day, and fall asleep. It is a sleep disorder, like insomnia (trouble sleeping at night, or waking up during the night), and falling to sleep during the day (called narcolepsy), but hypersomnia is not to be confused with these.
Hypersomnia affects about five percent of the population, or about one of twenty people.[source?] Very often, people with sleep apnea suffer from hypersomnia. Hypersomnia can also happen alongside other conditions such as mood disorders for example.
If the hypersomnia is caused by a problem with the brain or nervous system, it is called primary hypersomnia. Narcolepsy is an example of a primary hypersomnia. If the hypersomnia is the effect of another condition, it is usually called secondary hypersomnia. Examples of secondary hypersomnia include someone losing consciousness because of epilepsy. Sleep apnea is one of the most common forms of secondary hypersomnia. Certain drugs can also cause (secondary) hypersomnia.
Primary hypersomnia is very rare. Secondary hypersomnia are quite common.
