Definition and Overview

Narcolepsy is a medical condition that makes a person suddenly fall asleep during the day. It occurs when the levels of neurotransmitters (hypocretins) that help regulate wakefulness are very low. This causes a person to lose control over his sleep-wake cycle. Thus, even if they had a refreshing sleep the night before, they still experience excessive daytime sleepiness and feel drowsy throughout the day. They also find it very difficult to stay awake for more than a couple of hours no matter where they are or what they are doing. Without meaning to, they can suddenly fall asleep while having dinner with family or cooking lunch. They can even doze off while driving or in a middle of a business meeting.

The disorder affects one in every 2,000 people in the United States. It can be either mild or severe. The most severe cases are the ones that have a great impact on many aspects of a person’s life. Many are unable to go to work or do the things that they find enjoyable. However, patients are able to live normal and active lives if the disorder is treated with medications.

Causes of Condition

Researchers are not sure why some people have low levels of hypocretins. However, some studies suggest a number of factors may play a role.

  • Autoimmune disorder - An autoimmune response can cause damage to neurons that produce hypocretins.

  • Swine flu - Many patients with swine flu present with low levels of hypocretins.

  • Vaccine against swine flu

  • Genetic factors

  • Hormonal changes, which can occur during menopause and puberty

  • Severe mental and physical stress

Key Symptoms

People with this disorder are usually:

  • Very drowsy and sleepy most of the day

  • Less alert and can’t focus on their activities

  • Lose muscle tone briefly - This usually occurs when a person gets too happy or excited. It is normal for them to fall especially when they suddenly laugh. This symptom can occur many times a day. However, it usually only lasts for a couple of minutes.

  • Can’t move or speak while falling asleep or when waking up

The disorder does not cause serious or long-term physical and health problems. However, it can keep a person from doing his normal activities. These include driving or even cooking because they could hurt themselves or others. This causes many to lose motivation and suffer from severe depression.

Who to See and Types of Treatments Available

People showing the above symptoms can consult a doctor specialising in sleep disorders. Sleep specialists diagnose the disorder with these procedures:

  • Review of the patient’s medical and sleep history

  • Polysomnography - This is commonly the first test used to diagnose a number of sleep disorders. It requires the patient to go to a sleep center where he will be monitored overnight. While asleep, the doctor will record his brain waves, heart rate, and oxygen level, as well as eye and leg movements.

  • Multiple sleep latency test (MSLT) - This test is also often called a daytime nap study. For this procedure, patients will take scheduled naps with two-hour breaks in between. The test measures how long it takes for a person to fall asleep. People with this brain disorder usually fall asleep and enter REM (rapid eye movement) sleep within 15 minutes. Thus, if the patient is still awake after 20 minutes, the doctor will rule out narcolepsy as the cause of symptoms.

The disorder is treated with drugs that work by:

  • Improving nighttime sleep

  • Stimulating the central nervous system

  • Helping patients stay awake during the day

  • Treating all symptoms

Many drugs used for the treatment of the disorder have side effects. These include sleepwalking, bed-wetting, dry mouth, and nausea. Doctors carefully explain these side effects to patients before they are placed on medical therapy. If patients suffer from severe side effects that they cannot tolerate, they are advised to go back to their doctor so they can be given substitutes.

Aside from medications, patients are also advised to:

  • Avoid taking drugs that can cause drowsiness

  • Follow their sleep schedule

  • Take scheduled naps during the day

  • Not smoke and drink alcohol

  • Eat a well-balanced diet

  • Exercise as often as possible

Narcolepsy cannot be cured. Most of its symptoms can be treated with medications and lifestyle changes, but they will not completely go away. In some cases, symptoms worsen before they improve.


  • Ropper AH, et al. Sleep and its abnormalities: Introduction. In: Adams & Victor’s Principles of Neurology. 10th ed. New York, N.Y.: The McGraw-Hill Companies; 2014.

  • Narcolepsy fact sheet. National Institute of Neurological Disorders and Stroke.

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