Narcolepsy – Definition, Causes, Symptoms, Diagnosis, and Treatment

Narcolepsy is a chronic neurological disorder that affects the brain’s ability to regulate the sleep/wake cycle. People who are affected by this condition often feel excessively tired during the day, even if they got enough sleep at night. This excessive sleepiness is not ordinary and feels more like a sleep attack, where the affected person cannot suppress the feeling of fatigue, and they may nod off for a few seconds to several minutes at a time.

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Last Updated: Thu, July 4, 2019

Narcolepsy is a chronic neurological disorder that affects the brain’s ability to regulate the sleep/wake cycle. People who are affected by this condition often feel excessively tired during the day, even if they got enough sleep at night. This excessive sleepiness is not ordinary and feels more like a sleep attack, where the affected person cannot suppress the feeling of fatigue, and they may nod off for a few seconds to several minutes at a time.

People with narcolepsy experience changes in the architecture of their sleep, especially in REM stages. Rapid eye movement (REM) sleep usually occurs every 60 to 90 minutes in people with regular sleep cycles, but in those affected by narcolepsy, it can happen only 10 minutes after falling asleep. Additionally, people may experience cataplexy, which is described as the weakness of muscles that enables a person to move while awake. This state is similar to the paralyzing of the muscles that happen during the REM stage, but since the brain has lost the ability to regulate sleep and wake cycle, it can randomly occur during wakefulness.

It is estimated that 135.000 to 200.000 people are affected by narcolepsy in the United States. However, some experts believe that the condition is underdiagnosed because it is often mistaken with psychiatric disorders, and that the number can be much higher. It affects males and females equally, and the first symptoms usually appear between the ages of 7 and 25.

The goal of this article is to educate people on the causes, symptoms, and the treatment of narcolepsy. Affected people go through many relationship, work, academic, and social problems because of the sleep attacks, and that can often lead to the feeling of embarrassment and impaired mental health. 

Types of Narcolepsy

There are two main types of narcolepsy:

A disorder known as secondary narcolepsy can arise from an injury to the hypothalamus, a brain region that plays a significant role in regulating sleep. Besides the standard symptoms, these individuals can also experience severe neurological problems and sleep for prolonged periods each night (more than 10 hours).


The symptoms start in early life, in most cases in the teenage period. Unfortunately, it is a lifelong condition, but it doesn’t necessarily get worse with age. Some symptoms improve over time, especially if the person follows the guidelines for narcolepsy management. The excessive daytime sleepiness is present in all the patients, but all other symptoms are only experienced by 10 to 25 percent of affected individuals. Symptoms include:

What Causes Narcolepsy?

There are several known causes of this disorder. Almost all people with type 1 narcolepsy have lower levels of a brain hormone hypocretin (orexin), which plays a vital role in regulating REM sleep and promoting wakefulness. Low levels of hypocretin do not describe type 2 narcolepsy, and its causes are not well understood. And even though we know that the balance of this naturally appearing hormone dictates the development of the condition, we are not entirely sure how it all works and why it happens. Several factors cause lower hypocretin levels, and they include:

Related Conditions

Idiopathic hypersomnia is a condition that falls into the same category of sleep disorders as narcolepsy (hypersomnias). It is characterized by episodes of extreme sleepiness that have no identifiable cause. It is different than narcolepsy because the patients never develop cataplexy, and they don’t have sudden sleep attacks. Many individuals experience prolonged periods of rest (more than 10 hours), and excessive sleepiness can disrupt many aspects of life. Standard treatment includes behavioral therapy and certain medications.

Obstructive sleep apnea is a sleep-related breathing disorder that is described by the temporary interruption and cessation of airflow. It is caused by the blockage in the upper airway, and the person affected by it often wakes up during the night short of breath and painting. The most visible sign of sleep apnea is loud snoring, and others include excessive daytime sleepiness, sleep fragmentation, irritability, poor concentration, and impaired cognition. Obesity and neck size are the most common causes of this disorder, and if untreated, it could lead to high blood pressure, and increased risk of heart disease, stroke, and diabetes. Luckily, positive air pressure therapy is very effective in treating obstructive sleep apnea.

Kleine-Levin syndrome is a rare disorder that mostly affects teenage males, and it’s characterized by the behavioral changes such as an increased sex drive, the need for excessive amounts of sleep (over 20 hours a day), and overeating. When awake, affected people seem very disoriented, show irritability, lack of emotions and energy, and may experience hallucinations. These episodes last for days or weeks, and then a person goes into a few months of normal behavior. The cause of Kleine-Levin syndrome is not known, and weirdly, in most cases, the condition disappears later in life.

Excessive daytime sleepiness is a symptom of many other disorders, including hypothyroidism, depression, delayed sleep phase syndrome, periodic limb movement disorder, and many others. Brain tumors, head trauma, cerebral arteriosclerosis, psychosis, and uremia can cause symptoms that resemble those of narcolepsy.


The diagnosis of narcolepsy consists of a comprehensive clinical study that has the goal to rule out other disorders that could be a potential cause of occurring problems. Since symptoms of narcolepsy appear in many different conditions, the diagnosis is not that simple. A physician will take a close physical exam, and also talk about the patient’s medical history and symptoms. They might ask them to fill out a sleep diary for a week or two, where a person can keep track of their sleeping habits. That includes sleeping and waking times, night disruptions, daily energy levels, nap, activity, and others. This data gives doctors more perspective and can help them plan the next steps.

An overnight sleep study called polysomnography is required to determine the cause of sleep disturbances. It is done in a specialized facility where the sleep technicians measure brain waves, respiration, heart rate, body and eye movement, snoring, and muscle tension, while you are sleeping. They can also determine characteristics of REM sleep that should begin after 60 to 90 minutes after falling asleep, but with narcolepsy, it happens approximately 15 minutes from the beginning. 

A multiple sleep latency test often happens the day after the sleep study. It measures the time it takes people to fall asleep during the day. Usually, there are 4 or 5 opportunities, and people with narcolepsy appear to fall asleep more easily. Also, they will achieve REM sleep during short naps, which is something that other people don’t experience.

Cerebrospinal fluid analysis is helpful with diagnosing narcolepsy, as low levels of hypocretin in a cerebrospinal fluid almost always indicate this disorder.


Unfortunately, there is no definite cure for narcolepsy, and people affected by it go through their lives trying to manage the symptoms. Luckily, excessive daytime sleepiness and cataplexy can be both controlled with medications, and with additional lifestyle changes, symptoms became reasonably tolerable.

Medications include:

Lifestyle Changes

Medication treatment works for most of the patients, but it is always recommended to combine with certain changes in life habits. These strategies can help manage occurring symptoms:

Safety precautions are essential for people with narcolepsy, especially when driving. Taking medication regularly and following other guidelines that a medical professional prescribed is vital, and minimizes chances of accidents. 

A person’s mental health can suffer when they have troubles maintaining work, intimate, and social relationships. People not familiar with this condition can find sleep attacks humorous, or see them as a sign of laziness, which can negatively affect people suffering from it. That is why the Americans with Disabilities Act require employers and schools to adjust the schedule to the affected person. They might be able to take scheduled naps and perform more demanding tasks when they are most alert. Educating others about narcolepsy is also useful so that these people don’t feel embarrassed or discluded. Additionally, numerous support groups offer emotional support and practical advice to help individuals cope with this disorder.

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Dusan is a biologist, a science enthusiast and a huge nature lover. He loves to keep up to date with all the new research and write accurate science-based articles. When he’s not writing or reading, you can find him in the kitchen, trying out new delicious recipes; out in the wild, enjoying the nature or sleeping in his bed.

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