- Persistent daytime sleepiness occurs in all people with narcolepsy.
- Narcolepsy can also cause cataplexy, brief episodes of muscle weakness triggered by strong emotions.
- In addition, narcolepsy can cause fragmented sleep with vivid dreams, and hallucinations and brief paralysis when dozing off or waking up.
- These symptoms typically begin between ages 10 and 20.
Symptoms of narcolepsy differ among individuals. In some, they are mild and may only cause bothersome sleepiness that is relieved by an occasional nap. In others, symptoms can be severe and impact many aspects of life. Symptoms include:
Everyone with narcolepsy has some daytime sleepiness, but the severity of sleepiness varies among individuals. In many, it is so intense that they frequently and unintentionally doze off while sitting in a class, riding in a car, or watching a movie. Many people with narcolepsy report their sleepiness is similar to the feelings that others report after staying awake all night.
This intense and persistent sleepiness often leads to inattention and drowsiness. Sometimes, people with narcolepsy can have “automatic behavior” in which they continue an activity, such as driving or taking notes in class, with little conscious awareness.
In younger children, sleepiness may have a different appearance. The child may be irritable, hyperactive, or have trouble paying attention in school. School-age children may resume napping habits from a younger age, and the naps may be long and unrefreshing.
Many other sleep disorders, such as obstructive sleep apnea, result in both poor quality and insufficient nighttime sleep. As a result, people with apnea often do not feel well rested when they wake, and are sleepy during the day. In contrast, people with narcolepsy usually feel alert upon waking but then feel sleepy throughout much of the day, even though they have had good quality, ample nighttime sleep.
Similarly, most individuals with narcolepsy find that a brief, 15- to 20-minute nap substantially improves their alertness for the next one to two hours. This suggests that the sleepiness of narcolepsy is caused by a problem with the brain circuits that normally promote full alertness, rather than poor quality or insufficient sleep.
About half of all people with narcolepsy have cataplexy: episodes of muscle weakness that are usually triggered by strong emotions. The weakness typically builds up over several seconds and then lasts up to one or two minutes. Some people have only one or two episodes of cataplexy their whole lives; in others, cataplexy can occur up to 20 times each day. Cataplexy usually develops a few months after the onset of sleepiness, though sometimes the first episode of cataplexy will occur many years after sleepiness begins.1
In its severe form, cataplexy can cause weakness of the face, limbs, and trunk, leading an individual to slump to the ground, awake but unable to talk or move for up to one or two minutes. More commonly, the episodes are less severe and may simply cause some slurred speech, and weakness in the face, neck, or arms. These milder episodes are known as partial cataplexy.
In contrast to fainting or falling asleep, consciousness is fully preserved during cataplexy. With longer episodes, which are rare, some people can have dream-like hallucinations.
Quite often, episodes of cataplexy are triggered by positive emotions associated with heartfelt laughter, joking, or getting a sudden surprise such as unexpectedly seeing a friend2. Less commonly, cataplexy can occur with negative emotions such as intense frustration or anger. These triggers vary among people, and individuals with narcolepsy often come to recognize the conditions most likely to bring about their episodes.
In younger children, cataplexy is often triggered by positive emotions, such as feelings of excitement while playing a video game. The characteristics of cataplexy can be different in children. In addition to the transient muscle weakness that can occur, mild weakness can last for hours, with a slack face, half-closed eyes, and a wobbly, unsteady gait3. For unclear reasons, some children may slightly stick out their tongue during an episode.
Hallucinations and vivid dreams
Many people with narcolepsy have dream-like hallucinations just as they are falling asleep or waking up. (Hallucinations when falling asleep are known as hypnagogic; when waking up, hypnopompic.) These hallucinations can be quite vivid and may be frightening, such as a sense of a threatening stranger or dangerous animal in the room. Upon waking, it can take a few minutes to shake off the fear and appreciate that it was just a hallucination. Most likely, these hallucinations are rapid-eye-movement (REM) sleep-like dreams occurring when an individual is only half-awake.
Similarly, many people with narcolepsy have very vivid and intense dreams and nightmares while sleeping. In fact, some dreams are so lifelike that it can be hard to tell them from reality. For young children with narcolepsy, differentiating vivid dreams from reality can be especially difficult.
Sleep paralysis is an inability to move when on the edge of sleep. It can happen as someone is drifting off to sleep or waking up and usually lasts no more than a minute. When sleep paralysis first occurs, it can be quite frightening, especially as it sometimes includes a sensation of having difficulty breathing. Most likely, this is caused by an intrusion into wakefulness of the normal paralysis that occurs during REM sleep.
Disrupted Nighttime Sleep
People with narcolepsy are very sleepy during the day, yet many have trouble sleeping through the night. They may experience fragmented sleep—waking up several times each night for 10–20 minutes—that can worsen daytime sleepiness.
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- Overeem S, van Nues SJ, van der Zande WL, Donjacour CE, van Mierlo P, Lammers GJ. The clinical features of cataplexy: a questionnaire study in narcolepsy patients with and without hypocretin-1 deficiency. Sleep Med 2011; 12:12–8.
- Plazzi G, Pizza F, Palaia V, Franceschini C, Poli F, Moghadam KK, Cortelli P, Nobili L, Bruni O, Dauvilliers Y, Lin L, Edwards MJ, Mignot E, Bhatia KP. Complex movement disorders at disease onset in childhood narcolepsy with cataplexy. Brain 2011; 134:3480–92.
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