Imagine listening to a funny joke, then in the middle of laughing, your legs suddenly buckle and you are unable to move for the next several minutes. Maybe you are in class, but you are incredibly drowsy and finally just can't stay awake even though you had plenty of sleep the night before. These are examples of what people with narcolepsy experience.

People with narcolepsy have trouble staying awake; they often feel drowsy and fall asleep, even in the middle of the day, sometime in the middle of activities that produce strong emotions. It is thought that narcolepsy occurs when rapid eye movement (REM) sleep occurs while people are awake. Although the cause of narcolepsy is unknown, it does occasionally run in families. If one person in a family has the disorder, another relative may be susceptible to developing it if certain environmental triggers occur.


  • Excessive daytime sleepiness: people may fall asleep when they are doing a boring task or when they are working alone. These sleep attacks may become more frequent and occur at inappropriate and dangerous times such as when they are driving a car.

  • Cataplexy: sudden loss of muscle tone. Loss of muscle tone in the legs may cause a person to fall down. In people with normal sleep/wake functioning, loss of muscle tone is associated exclusively with REM sleep.

  • Sleep paralysis: lack of muscle tone in which people cannot move their limbs immediately after waking up or just before they fall asleep.

  • Hypnagogic hallucinations: dreamlike visual, auditory or tactile hallucinations in which elements of the waking world are incorporated just before falling asleep.


Medications such as stimulants (amphetamines, Ritalin) that increase alertness are often used to treat narcolepsy. However, stimulants may cause side effects including headaches, nervousness, and mood changes. Antidepressant medication is also used to treat narcolepsy. A new drug called Provigil was approved by the US Food and Drug Administration in late 1998. Provigil promotes wakefulness and appears to have fewer side effects than stimulants such as amphetamines.

In the Sleep Clinic at Stanford University, Doberman dogs that have narcolepsy are bred. Work with these animals has led to the discovery of the gene for narcolepsy.

Fast Facts

  • Humans spend approximately 1/3 of their lives asleep.
  • Narcolepsy is a lifelong disorder that affects approximately 1 in every 2000 people in the US.
  • Many people with narcolepsy go through their lives undiagnosed.
  • Symptoms of narcolepsy are usually first seen during the adolescent years.
  • Narcolepsy has been observed in humans and a few other species of animals, including dogs.
  • Narcolepsy has both genetic and sporadic forms.
  • The severity of the disorder varies from person to person.
  • Narcoleptics have 10 times the rate of automobile accidents as non-narcoleptics.
  • A description of narcolepsy in a mother and a son dates back to 1887.

Did you know?

Narcolepsy was first described in the 1880s by French physician Jean-Baptiste Edouard Gelineau.


  1. Center for Narcolepsy, Stanford University
  2. Narcolepsy and Sleep

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By Ellen Kuwana, Neuroscience for Kids Staff Writer