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Narcolepsy Causes and Risks

Medically Reviewed by Neha Pathak, MD on June 30, 2021

Narcolepsy is a chronic sleep disorder that makes you extremely sleepy during the day. Doctors don’t know what causes it. But they do understand some of the risk factors and triggers that may bring on the disease.

Approximately 135,000 to 200,000 people in the United States have narcolepsy. And there are likely more -- many cases go undiagnosed or are misdiagnosed, especially in children.

Some people with narcolepsy have symptoms in addition to their sleepiness, including sudden loss of muscle tone (cataplexy), momentary paralysis when falling asleep or waking up, and vivid hallucinations.

There isn’t a cure for narcolepsy, but your doctor can prescribe medications that can help you stay awake and learn ways to manage your symptoms so you can do the activities you enjoy.

Why Narcolepsy Happens

Your genes, immune system, and environment all seem to play a possible role in narcolepsy. There are two types of narcolepsy, and one type seems to be more closely linked to genetic and immune system response.

Some of the known triggers and links to narcolepsy include:

Low levels of a brain chemical and autoimmune disorders. If you have type 1 narcolepsy, you’re more likely to have cataplexy, which is a sudden loss of strength and muscle tone that can make you fall or become weak. People with this type of narcolepsy also have low levels of a brain chemical called hypocretin, which helps to control sleep function.

Doctors don’t know what causes low levels of hypocretin, but they think it may be tied to an autoimmune disorder. Autoimmune disorders happen when the immune system attacks healthy cells or tissue instead of an infection by mistake. In the case of narcolepsy, the immune system seems to attack the parts of the brain with hypocretin, which lowers the levels in your body.

Family history. Narcolepsy isn’t usually passed down from parent to child. Most cases are sporadic, meaning there isn’t any obvious reason they happen. But genetics do seem to play some role in the condition. You’re at an increased risk of having the condition if a family member has type 1 narcolepsy.

Brain injuries. A traumatic brain injury, tumor, or other disease or medical condition that impacts the part of the brain that regulates sleep may also lead to narcolepsy.

Hormone changes. Sudden, large, or intense hormone changes -- like the processes of puberty or menopause -- may also trigger narcolepsy.

An infection. Some people have gotten narcolepsy after having an infection, such as strep throat or the swine flu.

2009 flu vaccine used in Europe. After European health officials gave a flu vaccine called Pandemrix in 2009, researchers found that people who got it had a higher risk of narcolepsy. The vaccine was created for the H1N1 influenza pandemic. It was not used in the United States.

Show Sources

SOURCES:

Merck Manuals: “Narcolepsy.”

National Institute of Neurological Disorders and Stroke: “Narcolepsy Fact Sheet.”

National Heart, Lung, and Blood Institute: “Narcolepsy.”

MedlinePlus: “Narcolepsy.”

CDC: “Narcolepsy Following 2009 Pandemrix Influenza Vaccination in Europe.”

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