Narcolepsy is a chronic (long-term) disorder that causes periods of extreme daytime sleepiness, including sudden brief episodes of deep sleep. People who have narcolepsy usually feel refreshed after a brief nap or a full night’s sleep but become sleepy again soon after.
Narcolepsy can greatly affect your daily life and may be dangerous, as it can make you fall asleep without warning during routine activities, such as eating, working, or driving. There is no cure for narcolepsy, but medicines and healthy lifestyle changes can help you manage the condition.
The most common symptoms of narcolepsy include:
- Extreme daytime sleepiness
- Falling asleep without warning, called sleep attacks
- Difficulty focusing or staying awake
- Waking often at night
Other common symptoms that occur when falling asleep or waking up are hallucinations and sleep paralysis, which is a feeling of being awake but unable to move for several minutes. Rarely, people who have narcolepsy may experience cataplexy, which is a sudden loss of muscle tone leading to weakness and loss of voluntary control over the muscles. It can occur with strong emotions such as laughter, fear, stress, anger, or excitement.
To diagnose narcolepsy, your healthcare provider will ask about your medical and family history, do a physical exam, and recommend some of the following tests or studies.
- An overnight sleep study helps providers understand your sleep cycle.
- A sleep test looks at daytime naps to identify if you sleep well or if your sleep is disturbed for some reason, or if you move quickly into rapid eye movement (REM) sleep phase.
- A spinal fluid test checks your hypocretin levels. Hypocretin is a neurotransmitter that helps regulate your sleep. If your hypocretin levels are normal, your provider may give you a device called an actigraph to wear for several days or weeks. You wear the actigraph on your wrist like a watch. The actigraph tracks and records your movements and rest periods throughout the day.
- Your provider may also ask you to track your sleep habits in a sleep diary.
Causes and risk factors
Narcolepsy is usually caused by low levels of a neurotransmitter called hypocretin that helps you stay awake by keeping your brain from entering a deep state of sleep. Sometimes people have narcolepsy that is not caused by low hypocretin levels. In that case, the reason for the condition may not be known.
Your family history or environment can raise your risk of narcolepsy. Narcolepsy may also occur after an upper airway infection or, rarely, because of a head injury, sarcoidosis, a stroke, or another medical condition.
Narcolepsy cannot be cured, but medicine and healthy sleep habits can help improve your sleep and quality of life.
Medicines used to treat narcolepsy include:
- Stimulants, or wakefulness-promoting agents, to treat daytime sleepiness
- Depressants such as sodium oxybate to treat daytime sleepiness and cataplexy
- Sedatives to improve nighttime sleep
Daytime sleepiness often improves with enough good-quality sleep at night and scheduled naps during the day.