What is narcolepsy?
Narcolepsy is a neurological (nervous system) disorder that affects the control of sleep and wakefulness. People with narcolepsy experience a great deal of daytime sleepiness and uncontrollable episodes of falling asleep during the daytime, even though they have had enough sleep. These sudden sleep “attacks” may occur during any type of activity and at any time of the day.
Who gets narcolepsy?
Approximately 1 in 2,000 Americans has narcolepsy. The risk of developing narcolepsy is greater in first-degree relatives (i.e., parents, siblings, offspring) of narcoleptics (people who have narcolepsy). Narcolepsy can occur in people of all ages, but the first sign of daytime sleepiness usually appears in the teenage years or twenties. In many cases, narcolepsy is not diagnosed, and therefore, is not treated.
What causes narcolepsy?
Scientists have discovered that animals and humans with narcolepsy have a loss of a neuropeptide (chemical signal) in the brain called hypocretin. Hypocretin is important for stabilizing wake and rapid eye movement (REM) sleep states. A shortage causes excessive sleepiness, and features of REM sleep (also called “dreaming sleep”) become present during wakefulness.
What are the symptoms of narcolepsy?
Symptoms of narcolepsy include:
- Excessive daytime sleepiness (EDS) — Almost all patients with narcolepsy have this symptom. In general, EDS interferes with normal activities (work, school, etc.) every day, whether or not patients get enough sleep at night. People with EDS report mental cloudiness, a lack of energy and concentration, memory lapses, a depressed mood, or extreme exhaustion.
- Cataplexy — This symptom consists of a sudden loss of muscle tone that leads to feelings of weakness and a lack of voluntary muscle control. The muscle tone is lost as a result of strong emotions, such as laughter, joking, surprise, or anger. Attacks can occur at any time the person is awake. The attacks range from a brief buckling of the knees or slackness in the jaw to total paralysis with collapse. Cataplexy usually lasts a few seconds to several minutes. The rate of attacks ranges from a few in a lifetime to several per day. Cataplexy occurs in at least 60% of people with narcolepsy.
- Disrupted nighttime sleep — This symptom occurs in 60% to 90% of patients. Awakenings may be frequent but are generally brief, and the patient is often unaware that they have taken place.
Sleep paralysis — This symptom, which affects approximately 60% of narcoleptics, involves the temporary inability to move or speak while falling asleep or waking up. There is often a feeling of being unable to breathe, which can be frightening. Episodes of sleep paralysis usually go away in a few minutes.
- Hallucinations — Usually, these delusional experiences are vivid and may be frightening. The hallucinations occur when the person falls asleep, or wakes up. Hallucinations can be visual (seen), tactile (felt), or auditory (heard). Examples include seeing a person or animal in the room, feelings of levitation (floating) or sensations of being touched, and hearing an alarm or voices. These types of hallucinations occur in approximately 60% of narcoleptic patients. The hallucinations are called “hypnagogic hallucinations” when they occur while the person is falling asleep, and “hypnopompic hallucinations” when they happen during awakening.
How is narcolepsy diagnosed?
Narcolepsy is diagnosed after the doctor performs a detailed medical and sleep history, physical examination, and sleep testing (which is performed in a sleep disorders center).
Two essential tests for confirming a diagnosis of narcolepsy are the polysomnogram (PSG) and the multiple sleep latency test (MSLT):
- The PSG is an overnight test that takes continuous multiple measurements while a patient is asleep to record abnormalities in the sleep cycle. A PSG can help reveal disturbances in REM sleep that are commonly seen in narcoleptics, and can eliminate the possibility that symptoms are caused by another condition, such as obstructive sleep apnea. Most narcoleptics show disruptions in normal sleep patterns, with frequent awakenings.
- The MSLT is performed during the day to measure a person's tendency to fall asleep, and to determine whether isolated elements of REM sleep intrude at inappropriate times during the waking hours. As part of the test, an individual is asked to take five short naps, usually scheduled two hours apart. Narcoleptics generally fall asleep with every opportunity. They also quickly enter into REM sleep, known as sleep-onset REM periods (SOREMPs). Whenever possible, medications that reduce the amount of REM sleep, such as wake-promoting agents and antidepressants, should be discontinued for at least two weeks before testing.
How is narcolepsy treated?
The treatment of narcolepsy is aimed at improving alertness during the desired time of the day, based on the individual's needs and lifestyle. People with narcolepsy should make the most of the quality and quantity of sleep by taking the following steps:
- Keep to a regular sleep-wake schedule.
- Avoid intentional sleep loss, such as staying awake late on weekends.
- Avoid alcohol and other central nervous system depressants.
- Modify work and school schedules if possible, such as avoiding early morning classes.
- Take short naps (20-30 minutes) as needed to avoid unintentional sleep attacks.
- Use modest amounts of caffeine to promote alertness as needed.
- Operate motor vehicles and other heavy machinery with extreme caution and only when approved by your doctor.
In addition to these measures, wake-promoting medications or stimulants are often prescribed to improve daytime sleepiness. Examples include modafinil (Provigil®), armodafinil (Nuvigil®), methylphenidate (Ritalin®), and amphetamine agents. These medications can produce side effects similar to that of caffeine, such as agitation, nervousness, and palpitations. They are generally started at a low dose and increased gradually as needed. Careful monitoring is required, as high blood pressure and heart arrhythmias (irregular heartbeats) have been reported. Sodium oxybate (Xyrem®) is the only FDA-approved medication used to treat daytime sleepiness and cataplexy in patients with narcolepsy.
Cataplexy, hypnogogic hallucinations, and sleep paralysis have been treated traditionally with two classes of antidepressant medications: tricyclic antidepressants, such as protriptyline (Vivactil®) and clomipramine (Anafranil®), and selective serotonin reuptake inhibitors (SSRIs), like fluoxetine (Prozac®) and sertraline (Zoloft®). SSRIs generally have fewer side effects than tricyclic antidepressants.
Narcolepsy can be a draining disorder that interferes with a person’s ability to function in all aspects of life, including at school, home, on the job, and behind the wheel of a car. Teachers and bosses often view people with narcolepsy as lazy and unmotivated.
People with narcolepsy have a greater risk for motor vehicle accidents, occupational hazards, and academic underachievement. Therefore, prompt diagnosis and treatment is required. To achieve the highest degree of alertness and daytime functioning, it’s very important to communicate with your healthcare professional.
- National Institute of Neurological Disorders and Stroke: Narcolepsy Fact Sheet
- National Heart, Lung, and Blood Institute: What Is Narcolepsy?
- National Sleep Foundation: Narcolepsy and Sleep
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 12/11/2015...#12147