What is narcolepsy, symptoms & causes

Narcolepsy

Narcolepsy is a neurological disorder that affects the control of sleep and wakefulness. People with narcolepsy experience excessive daytime sleepiness and intermittent, uncontrollable episodes of falling asleep during the daytime. These sudden sleep attacks may occur during any type of activity at any time of the day.

In a typical sleep cycle, we initially enter the early stages of sleep followed by deeper sleep stages and ultimately (after about 90 minutes) rapid eye movement (REM) sleep. For people suffering from narcolepsy, REM sleep occurs almost immediately in the sleep cycle, as well as periodically during the waking hours. It is in REM sleep that we can experience dreams and muscle paralysis -- which explains some of the symptoms of narcolepsy.

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Narcolepsy usually begins between the ages of 15 and 25, but it can become apparent at any age. In many cases, narcolepsy is undiagnosed and, therefore, untreated.

What Causes Narcolepsy?

The cause of narcolepsy is not known; however, scientists have made progress toward identifying genes strongly associated with the disorder. These genes control the production of chemicals in the brain that may signal sleep and awake cycles. Some experts think narcolepsy may be due to a deficiency in the production of a chemical called hypocretin by the brain. In addition, researchers have discovered abnormalities in various parts of the brain involved in regulating REM sleep. These abnormalities apparently contribute to symptom development. According to experts, it is likely narcolepsy involves multiple factors that interact to cause neurological dysfunction and REM sleep disturbances.

What Are the Symptoms of Narcolepsy?

Symptoms of narcolepsy include:

Excessive daytime sleepiness (EDS): In general, EDS interferes with normal activities on a daily basis, whether or not a person with narcolepsy has sufficient sleep at night. People with EDS report mental cloudiness, a lack of energy and concentration, memory lapses, a depressed mood, and/or extreme exhaustion.

Cataplexy: This symptom consists of a sudden loss of muscle tone that leads to feelings of weakness and a loss of voluntary muscle control. It can cause symptoms ranging from slurred speech to total body collapse, depending on the muscles involved, and is often triggered by intense emotions such as surprise, laughter, or anger.

Hallucinations: Usually, these delusional experiences are vivid and frequently frightening. The content is primarily visual, but any of the other senses can be involved. These are called hypnagogic hallucinations when accompanying sleep onset and hypnopompic hallucinations when they occur during awakening.

Sleep paralysis: This symptom involves the temporary inability to move or speak while falling asleep or waking up. These episodes are generally brief, lasting a few seconds to several minutes. After episodes end, people rapidly recover their full capacity to move and speak.

How Is Narcolepsy Diagnosed?

A physical exam and exhaustive medical history are essential for proper diagnosis of narcolepsy. However, none of the major symptoms is exclusive to narcolepsy. Several specialized tests, which can be performed in a sleep disorders clinic or sleep lab, usually are required before a diagnosis can be established. Two tests that are considered essential in confirming a diagnosis of narcolepsy are the polysomnogram (PSG) and the multiple sleep latency test (MSLT).

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You say you are able to function well with fewer than seven hours of sleep. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

Since you usually get too little sleep, please talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have insomnia or other conditions affecting your sleep.

Sleep deprivation can have both short- and long-term consequences. Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's not surprising you feel that you're not functioning at your best today. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's good that you usually do get more sleep, since sleep deprivation can have both short- and long-term consequences. Learn more about the health consequences of sleep loss. And if you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's good that you usually do get more sleep because sleep deprivation can have both short- and long-term consequences. Learn more about the health consequences of sleep loss. And if you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

Since you usually get less sleep, please talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have difficulty sleeping or have insomnia or other sleep disorders.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's wonderful that you got a good night's sleep last night. Many people struggle to do so. Having a good sleep routine often is the key to getting the quality sleep night after night that your body needs for optimal health. Whether your sleep routine involves taking a warm bath, reading a book, or meditating, it's important to keep your bedtime and routine consistent every night and wake up around the same time every morning.

Click here to read more about the importance of sleep. If you're concerned about having trouble falling asleep, staying asleep, or sleeping too much, assess your risk for a sleep disorder.

It's unfortunate you're not functioning at your best today. You say you had a good quantity of sleep last night, but maybe the quality of your sleep is not as good as it could be? Having a good sleep routine — including a consistent bedtime and wake time — often is the key to getting the quality sleep night after night that your body needs for optimal health. Since you usually sleep this amount, if you often aren't feeling your best, you should consider talking to your doctor. Could you have an underlying condition? Are you feeling anxious or depressed? Have you taken medication that disrupted your sleep? Do you or could you have sleep apnea? Or do you naturally require a little bit more sleep?

Although sleep is crucial for optimal health, some research suggests that sleeping too much can also have negative consequences. Learn more about sleep. If you're concerned about having trouble falling asleep, staying asleep, or sleeping too much, assess your risk for a sleep disorder.

It's unfortunate you're not functioning at your best today. You say you had a good quantity of sleep last night, but maybe the quality of your sleep is not as good as it could be? Having a good sleep routine — including a consistent bedtime and wake time — often is the key to getting the quality sleep night after night that your body needs for optimal health. Since you usually sleep longer, if you often aren't feeling your best, you should consider talking to your doctor. Could you have an underlying condition? Are you feeling anxious or depressed? Have you taken medication that disrupted your sleep? Do you or could you have sleep apnea? Or do you naturally require a little bit more sleep?

It's wonderful that you got a good night's sleep last night. Many people struggle to do so. Having a good sleep routine often is the key to getting the quality sleep night after night that your body needs for optimal health. Whether your sleep routine involves taking a warm bath, reading a book, or meditating, it's also important to keep bedtime consistent and wake up around the same time every morning.

Although sleep is crucial for optimal health, some research suggests that sleeping too much can have negative consequences. Learn more about sleep. If you're concerned about having trouble falling asleep, staying asleep, or sleeping too much, assess your risk for a sleep disorder.

Since you usually get less sleep, please talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have insomnia, another sleep disorder, or conditions affecting your sleep.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

Since you usually get less sleep, talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have insomnia or another sleep disorder or conditions affecting your sleep.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

SOURCES:

Centers for Disease Control and Prevention (CDC). Effect of short sleep duration on daily activities--United States, 2005-2008. MMWR Morb Mortal Wkly Rep 2011; 60:239.

Carskadon, MA, Dement, WC. Normal Human Sleep: An Overview. In: Principles and Practices of Sleep Medicine, Fifth, Kryger, MH, Roth, et al. (Eds), Elsevier Saunders, St. Louis, MO 2011. p.16.

Harvard University: "Sleep, Performance, and Public Safety."