Narcolepsy: What It Is, Causes, Symptoms & Treatment (2024)

What is narcolepsy?

Narcolepsy is a sleep disorder that causes an urge to fall asleep suddenly during the daytime that’s almost impossible to resist. Although this condition isn’t common, it’s widely known because of its symptoms and how they happen. Narcolepsy is usually treatable, but the condition can still cause severe disruptions in your life, ability to work and social relationships.

What are the symptoms of narcolepsy?

There are four main symptoms of narcolepsy, but most people with this condition don’t have all four. The four symptoms are:

• Excessive daytime sleepiness. This symptom happens to everyone with narcolepsy. People with narcolepsy and experts on the condition often describe these as “sleep attacks.”
• Sudden muscle weakness (cataplexy). This can have mild effects, affecting one side of your body or only light muscle weakness. (See below for more about this symptom.)
• Sleep-related hallucinations. These happen right after falling asleep or right before waking up.
• Sleep paralysis. When you have this symptom, you’ll wake up — sometimes fully, but not always — but find yourself unable to move. (See below for more about this symptom.)

More about cataplexy

There are two main types of narcolepsy, and whether or not you have cataplexy separates the two. The two types are:

• Narcolepsy type 1: This form involves cataplexy. About 20% of narcolepsy cases are type 1.
• Narcolepsy type 2: This form doesn’t involve cataplexy. The majority of narcolepsy cases — about 80% — are type 2.

Under ordinary circ*mstances, your brain shuts down most muscle control in your body to keep you from acting out your dreams. People with cataplexy will have sudden muscle weakness, similar to how your body blocks movements during REM sleep.

Mild cataplexy may only affect your face and neck — such as your jaw dropping involuntarily — or just one side of your body. Severe cataplexy can make you collapse to the ground, which can lead to injuries. These events usually last under a few minutes, but you may not be able to move or talk at all during that time.

Cataplexy is also unusual because certain emotions cause it to happen. Positive emotions are most likely to trigger cataplexy, especially laughing, making jokes or other humor-related behavior. Surprise, fear and anger can also trigger cataplexy, but aren’t as likely to do so.

Cataplexy can take slightly different forms in children and in people whose symptoms started within the past six months. For them, cataplexy can look like sudden, uncontrollable grimacing or face-scrunching, sticking out their tongue or loss of muscle tone (making muscles feel soft and limbs “floppy”) throughout their body without an emotion-related cause.

More about sleep paralysis

Your brain shuts down muscle control in your body to keep you from acting out your dreams, but this should end when you wake up. However, if you have sleep paralysis, your body doesn’t regain muscle control as it should. You can still breathe and move your eyes, but you can’t talk or move the rest of your body.

Hallucinations during sleep paralysis are very common, and they’re often vivid and extraordinarily frightening. Fortunately, sleep paralysis is usually very short-lived, lasting only a couple of minutes at most (though people with this often describe that it feels longer).

Other symptoms

In addition to the four main symptoms, some other symptoms or behaviors are common in people with narcolepsy. Some of the more common or easily noticeable behaviors include:

• Automatic movements. People with narcolepsy can often fall asleep, but may keep moving parts of their body like their hands.
• Amnesia or forgetfulness. It’s common for people with this condition to not remember what they were doing right before falling asleep.
• Sudden outbursts around sleep attacks. A person with narcolepsy may suddenly speak up and say something (usually words or phrases that are nonsensical or unrelated to what’s happening around them). When someone with narcolepsy does this, it might startle them back to being fully awake, but most people who do this also don’t remember doing it.

Who does narcolepsy affect?

Healthcare providers usually diagnose narcolepsy in people between the ages of 5 and 50. However, it’s most likely to appear in young adults in their late teens and early 20s. Men and people assigned male at birth (AMAB) have a higher risk of developing narcolepsy.

How common is narcolepsy?

Narcolepsy is uncommon. Available research shows that it affects 25 to 50 people out of every 100,000 worldwide. However, this condition often takes years to diagnose, so the actual number of people with it is difficult to estimate.

How does narcolepsy affect my body?

To understand narcolepsy, it helps to know more about the way the human sleep cycle works. That cycle involves the following stages:

• Stage 1: Light sleep. This short stage begins right after you fall asleep and accounts for about 5% of your total sleep time.
• Stage 2: Deeper sleep. This stage is deeper and makes up about 45% to 50% of all the time you spend sleeping (this number goes up as you get older).
• Stage 3: Slow wave sleep. This stage makes up about 25% of the time you spend sleeping (this number goes down with age). It’s very hard to wake someone up in stage 3 sleep, and waking up directly from it usually causes “sleep inertia,” a state of “mental fog” and slowed thinking. This is also the stage where sleepwalking or sleeptalking typically happens.
• REM sleep: REM stands for “rapid eye movement.” This stage is when you dream. When a person is in REM sleep, you can see their eyes moving beneath their eyelids.

If you don’t have narcolepsy, you typically enter stage 1 when you fall asleep and then move into stages 2 and 3. You’ll cycle between these stages and ultimately go into REM sleep and start dreaming. After the first REM cycle, you start a new cycle and go back into stage 1 or 2. One cycle normally takes about 90 minutes before another begins. Most people go through four or five cycles per night (assuming they get a full eight hours).

If you have narcolepsy, your sleep cycle doesn’t happen like that. Instead, you’ll go into the REM stage shortly after falling asleep. The rest of the night, you’ll sleep only in short stretches, often without going through the typical sleep cycle.

With narcolepsy, no matter how well you sleep at night, you’ll feel extremely sleepy during the daytime. That urge to fall asleep is usually impossible to resist, but these sleep periods are also short (about 15 to 30 minutes) during the day. Once you wake up, you’ll feel rested and ready to resume whatever you were doing before. However, this happens several times during the day, which is why narcolepsy is so disruptive.