How Common Is Narcolepsy?
Reviewed by: HU Medical Review Board | Last reviewed: June 2020 | Last updated: January 2021
Narcolepsy is a sleep disorder in which the brain fails to control sleep-wake cycles. It causes the person to feel very sleepy during the day and wake up often during the night.
People with narcolepsy fall asleep unwillingly and unexpectedly, often many times a day. These are sometimes called “sleep attacks.” This can occur in the middle of activities, such as driving, eating, working, or talking. Some people with narcolepsy also have cataplexy, which means they go limp or cannot move after a strong emotion. Narcolepsy is a life-long problem.
How common is narcolepsy?
Between 135,000 and 200,000 people in the U.S. have narcolepsy. However, since many people are undiagnosed, these numbers may be much higher. Narcolepsy is often incorrectly diagnosed as a mental health condition or seizure disorder.1
It is equally common in men and women.1-2
People with narcolepsy are more likely to have other sleep disorders such as sleep apnea, restless legs syndrome, sleepwalking, periodic limb movements, and REM sleep disorder.2
At what age does narcolepsy occur?
Symptoms most often begin in the teens and early 20s but may begin in childhood or after age 40. About half of all people with narcolepsy develop symptoms as a teenager. It may take 5 to 15 years to get an accurate diagnosis of narcolepsy.3-4
How does narcolepsy affect different ethnicities?
Not much is known about how narcolepsy affects different populations. Doctors do know that it is more common in Japan and less common in Israel compared to the U.S. and Europe.3
What causes narcolepsy?
Doctors believe that most narcolepsy is caused by a combination of genetics and environment. Most people with narcolepsy have no family history of the condition. There are 2 main types of narcolepsy:1-2
Type 1 narcolepsy
Type 1 narcolepsy used to be called narcolepsy with cataplexy. It is caused when the nerve cells lose almost all of the brain hormone hypocretin. Hypocretin is also called orexin and helps the body control sleep. Doctors believe type 1 narcolepsy may be caused by a genetic mutation, by an autoimmune reaction, or some combination of the two.
Type 2 narcolepsy
Type 2 narcolepsy used to be called narcolepsy without cataplexy. Doctors do not fully understand what causes Type 2 narcolepsy. It sometimes occurs after a stroke or tumor. Most people with this type of narcolepsy have less severe symptoms.
Narcolepsy may also be caused by other health conditions that damage the brain such as brain injury, autoimmune disorders, or Parkinson’s disease.1-5
What role do genes and autoimmunity play in narcolepsy?
Doctors know that some cases of narcolepsy develop after cold and flu season. They also know that some people with type 1 narcolepsy test positive for the genetic mutation HLA DQB1*0602. Together, this suggests that people with a genetic predisposition are at risk for developing narcolepsy after certain infections.
Studies have shown that people with narcolepsy test for high levels of anti-streptolysin O antibodies, which means they recently had an infection such as strep throat. Also, after the H1N1 flu epidemic in 2009, doctors recorded an increase in the number of new cases of narcolepsy.1-2
What are the costs of narcolepsy?
Narcolepsy can be hard to manage, even with drugs and lifestyle changes. Other people may find it hard to understand or be patient. Therefore, social stigma around the condition makes depression and anxiety common among those with narcolepsy.
Children with narcolepsy often perform poorly in school, and adults find it hard to work. Everyday activities such as driving, exercise, or cooking may not be safe for someone with narcolepsy. Current research is focused on finding new and better ways to treat this disorder.