Imagine being drowsy all day, even after a full night’s sleep. For people with narcolepsy, this exhaustion never fully fades. Narcolepsy is a neurological disorder that disrupts the brain’s ability to manage the sleep cycle, leading to excessive daytime sleepiness (EDS) and sudden loss of muscle tone, known as cataplexy. Narcolepsy is a chronic condition, meaning that it’s usually lifelong. However, it doesn’t typically worsen with age and may even improve over time.

Read on to learn eight facts about narcolepsy including information on causes, diagnosis, and treatment.

1. Narcolepsy Was First Thought To Be a Seizure Disorder

The first two mentions of narcolepsy in medical literature were published in 1877 and 1880. In 1877, Carl Westphal, a German scientist, wrote about two individuals with symptoms of narcolepsy with cataplexy. Westphal described the episodes as “epileptic attacks” and noted the individuals’ sleep attacks. Early reports of narcolepsy associated the condition with seizure disorders because of cataplexy episodes.

In 1880, French physician Jean-Baptiste-Edouard Gélineau first used the term narcolepsy (“narcolepsie” in French) to describe symptoms like cataplexy and sleep paralysis. Gélineau is credited with discovering that narcolepsy was a disease separate from epilepsy.

Scientific understanding of narcolepsy and all sleep disorders expanded greatly when scientists identified rapid eye movement (REM) sleep in the early 1950s. During the 1960s and 1970s, researchers at Stanford University helped establish sleep medicine as its own field and introduced sleep studies that are used to diagnose narcolepsy.

2. There Are 3 Types of Narcolepsy

There are two major types of idiopathic narcolepsy — type 1 and type 2. Idiopathic means that the exact cause of the condition is unknown. Understanding the different types of narcolepsy can make it easier to see how symptoms can vary from person to person.

• Narcolepsy type 1 — This type was previously referred to as narcolepsy with cataplexy because that is one of the key features. Other key features of type 1 narcolepsy include EDS and low levels of a brain chemical called hypocretin. This chemical is necessary for regulating sleep.
• Narcolepsy type 2— Most people with narcolepsy have type 2, previously known as narcolepsy without cataplexy. People with type 2 narcolepsy have similar symptoms to type 1, including EDS. However, they usually don’t have cataplexy or low hypocretin levels.

Secondary narcolepsy is a third type of narcolepsy that’s caused by damage or injury to the hypothalamus — the part of the brain that controls sleep function. Conditions that can cause secondary narcolepsy include:

• Concussions
• Stroke
• Traumatic brain injury
• Brain tumors

People with secondary narcolepsy share many of the same symptoms as those with types 1 and 2. However, they may also need more sleep than people with other types of narcolepsy and may sleep 10 or more hours per day.

3. Excessive Daytime Sleepiness Is the Main Symptom

Symptoms of narcolepsy can vary from person to person. For example, type 1 narcolepsy includes cataplexy, while type 2 does not. But EDS — constant exhaustion that doesn’t go away, no matter how much sleep you get — affects everyone with narcolepsy. It’s often the first symptom to appear, followed by others like:

• Sleep attacks — Sleep attacks are part of the EDS that characterizes narcolepsy. These “attacks” are the sudden inability to stay awake during the day.
• Sleep paralysis — Sleep paralysis is when a person can’t speak or move either when waking up or falling asleep. Most sleep paralysis episodes only last a few seconds but can occasionally last longer.
• Hallucinations — Vivid hallucinations can occur when a person with narcolepsy wakes up (hypnopompic hallucinations) and when they fall asleep (hypnagogic hallucinations). Hallucinations that occur in narcolepsy are similar to dreams that would happen during REM sleep, except they occur during a semi-awake state.
• Sleep disruptions — Often, people with narcolepsy experience disrupted nighttime sleep, fragmented sleep, or insomnia. Individuals with narcolepsy can fall asleep quickly but may wake frequently throughout the night.
• Automatic behaviors — These are when someone experiences a brief sleep episode in the middle of an activity and they continue the activity, but will not remember what they were doing. Automatic behaviors can be dangerous if they happen while driving.

Another major symptom is cataplexy, but not everyone has this. Cataplexy is a sudden loss of muscle control while you’re awake and fully conscious. It’s often caused by strong emotions. Cataplexy episodes can last for a few seconds to a few minutes. The severity of an episode can range from mild symptoms (like eyelid drooping) to serious episodes that cause a fall. Symptoms of cataplexy usually go away on their own and aren’t dangerous as long as you have a safe place to fall.

4. The Cause of Narcolepsy Is Unknown

It’s understood that narcolepsy causes changes in the brain that make it difficult to regulate the sleep-wake cycle. However, it’s unclear what exactly causes these changes.

Narcolepsy type 1 is associated with low levels of hypocretin, also called orexin, because the body loses cells in the brain (neurons) that produce hypocretin. It is thought that these cells are lost due to an autoimmune process. This means that the immune system mistakenly attacks healthy cells that produce hypocretin, which causes the development of narcolepsy. Although it isn’t entirely clear what causes this autoimmune response, researchers think that a combination of inherited and environmental factors likely contributes.

Researchers think that certain infections may trigger the immune system to attack. This includes viral infections, such as H1N1 influenza, and bacterial infections, such as strep throat.

Up to 10 percent of people who are diagnosed with narcolepsy type 1 report having a close relative with similar symptoms. People who have a certain variation of the gene HLA-DQB1 are more at risk of developing narcolepsy. Most people who have narcolepsy have this genetic variation, but everyone who has this genetic change will develop a sleep disorder.

5. It’s a Rare Condition

Narcolepsy is rare, but many cases go unrecognized or are misdiagnosed. An estimated 126,000 people in the United States have been diagnosed with narcolepsy, though the true number may be higher. Although symptoms often begin in childhood, adolescence, or early adulthood, narcolepsy can develop at any age.

6. Receiving a Diagnosis Can Take a Long Time

Unfortunately, diagnostic delays have been common for people with narcolepsy. There is often a five- to 10-year delay in the diagnosis of narcolepsy. Out of all the people who have narcolepsy, researchers think that only 25 percent have been diagnosed and are receiving treatment.

This may be because people who have narcolepsy symptoms may be misdiagnosed with a different neurological disorder with similar symptoms, like ADHD or depression.

7. You Can Be Diagnosed With Sleep Studies and Other Tests

Although there are delays in the diagnostic process, there is a specific way doctors diagnose narcolepsy. This process involves a combination of your medical history and diagnostic sleep studies.

Medical History

A narcolepsy doctor or sleep specialist will take a detailed medical history and ask questions about your symptoms. They’ll also ask about your sleep history. Discussing your medical history and symptoms can help your health care provider determine the next steps for diagnosing your condition.

Sleep Studies

A polysomnogram (PSG) is an overnight sleep study used to measure nighttime sleep patterns. The PSG will record brain and muscle activity, eye movement, and breathing.

A multiple sleep latency test (MSLT) is usually conducted the day after a PSG. The test is used to evaluate EDS. You will be asked to take five short naps every couple of hours. The MSLT measures sleep latency — how quickly you fall asleep and the time it takes to enter REM sleep.

Other Tests

Your physician may conduct additional tests to diagnose your condition. These include:

• Hypocretin level testing — Your doctor may test your hypocretin levels via a lumbar puncture (also called a spinal tap). Low levels of hypocretin in cerebrospinal fluid indicate type 1 narcolepsy. This test is usually only done if other diagnostic tests are inconclusive.
• Genetic testing — When your symptoms and test results are inconclusive, your doctor may recommend genetic testing to determine if you have a genetic marker associated with narcolepsy.

8. There’s No Cure But Treatment Can Help

There’s no cure for narcolepsy, but symptoms can be managed. Narcolepsy is usually treated with a combination of medication and lifestyle changes.

Medications

The right medication for you will depend on your symptoms, age, and other conditions. Generally, the goal of prescribing medication for narcolepsy is to help people stay awake during regular waking hours or to help them be most alert during school, work, or other important times of the day.

These types of medications may be prescribed to help with your symptoms:

• Wakefulness medications
• Amphetamines or other stimulants
• Antidepressants
• Sodium oxybate

Lifestyle Changes

Alongside medical treatment, certain lifestyle habits can improve sleep. Here are some lifestyle changes you can make to help your symptoms:

• Go to bed and wake up at the same time each day to maintain a regular sleep schedule.
• Only take short daytime naps if needed.
• Get exercise daily, but ensure you finish exercising at least four to five hours before bedtime.
• Don’t drink alcohol or caffeine before bed.
• Avoid eating too close to bedtime, especially heavy meals.

Treatment for mental health conditions and any conditions related to narcolepsy are both important parts of your narcolepsy treatment plan. Talk to your doctor about how you can best manage your narcolepsy symptoms.

Find Your Team

On MyNarcolepsyTeam, the social network for people with narcolepsy and their loved ones, more than 11,000 members come together to ask questions, give advice, and share their stories with others who understand life with narcolepsy.

Are there any facts on this list that surprised you? What new facts have you learned about narcolepsy? Share your experience in the comments below, or start a conversation by posting on your Activities page.