Narcolepsy and idiopathic hypersomnia are the most common types of hypersomnia disorders.
Narcolepsy causes you to fall asleep throughout the day and disrupts nighttime sleep. Narcolepsy can also cause sleep paralysis -- a temporary inability to move -- and hallucinations, usually when you first wake up or are falling asleep.
- Type one narcolepsy may be accompanied by cataplexy (muscle weakness that can be triggered by strong emotions).
- Type two narcolepsy does not involve cataplexy.
Idiopathic hypersomnia causes you to feel extremely tired all the time.
Hypersomnia can also be brought on by medical conditions like traumatic brain injury, medication side effects, substance abuse, and other factors. Kleine-Levin syndrome is an extremely rare type of hypersomnia that can make you sleepy for days at a time.