Do you have narcolepsy? Take this test to screen for symptoms of excessive daytime sleepiness
- If you have narcolepsy, you will likely fall asleep suddenly during the day.
- You may also experience cataplexy, or the sudden loss of voluntary muscle control, which can lead to slurred speech or fainting.
- Here's how to know if you have narcolepsy and what you can do to treat this rare condition.
- This article was medically reviewed by Alex Dimitriu, MD, psychiatrist and founder of Menlo Park Psychiatry and Sleep Medicine.
Narcolepsy is a rare condition that will make someone fall asleep abruptly — even in the middle of the day during an activity.
It's possible to treat narcolepsy and manage your symptoms with lifestyle changes and medication in order to stay safe and healthy. Here's how to recognize the signs of narcolepsy and get the proper treatment.
What is narcolepsy?
Narcolepsy is a neurological disorder that causes you to fall asleep suddenly during the day, even in the middle of an activity. This condition affects about 1 in 2,000 people in the US, and the symptoms usually appear between the ages of 10 and 30.
People with narcolepsy can fall asleep while eating, walking, or even driving — making it potentially dangerous. As many as 50% of people with narcolepsy have experienced accidents or health risks from falling asleep during activities.
Symptoms of narcolepsy
Common symptoms of narcolepsy include:
- Excessive daytime sleepiness, or EDS, is the most recognizable symptom of narcolepsy, and occurs regardless of how much sleep you get at night. The urge to sleep comes on suddenly and a person with narcolepsy can go from awake and alert to asleep within a matter of minutes. You can take the following quiz, based on the Epworth Sleepiness Scale, to help determine if you're experiencing excessive daytime sleepiness:
- Cataplexy is the sudden loss of voluntary muscle control. This can lead to slurred speech, or in severe cases, you can even collapse. Unlike cataplexy due to seizures or fainting, you don't lose consciousness, and it only lasts for a few minutes. Some people with narcolepsy have multiple attacks of cataplexy each day while others have just one or two their whole lives.
- Sleep paralysis occurs right as you fall asleep, or right as you wake up. It is similar to cataplexy — in that you lose muscle control while you are conscious — but it happens for a few seconds or minutes while you are lying in bed.
- Hallucinations. Sometimes, visual hallucinations accompany sleep paralysis. The hallucinations can be vivid, as if you are dreaming without actually being asleep.
Diagnosis and narcolepsy tests
Narcolepsy is first diagnosed based on the symptoms and then can be confirmed with lab tests. If you are experiencing excessive daytime sleepiness, your primary care physician will likely refer you to a sleep specialist.
From there, one common test to diagnose narcolepsy is the Multiple Sleep Latency Test (MSLT). Basically, it tests how quickly you go into a deep sleep.
To do the MSLT, a sleep specialist will monitor you while you take five naps, two hours apart. If it takes you less than eight minutes to fall asleep on average, and you fall into REM sleep in at least two of the naps, you are considered to have narcolepsy. REM sleep can be detected by tracking your heart rate or brain waves using an ECG or EEG, or even watching for when your eyes flutter and move.
Doctors can also do a spinal tap to check your cerebral spinal fluid for hypocretin levels, but this is generally a last resort because it is more invasive and painful.
What causes narcolepsy?
There are two main types of narcolepsy: type 1 and type 2.
Type 1 narcolepsy
Type 1 narcolepsy is the most common type, affecting 60% to 90% of narcoleptics, and is caused by a deficiency of hypocretin, a neurochemical that helps regulate the sleep-wake cycle.
Hypocretins are produced in the part of the brain called the hypothalamus, which helps regulate sleep. In healthy people, hypocretins are released when you are awake, and they bind to neurons that promote wakefulness and suppress REM sleep.
During REM sleep, which typically occurs about 90 minutes after you fall asleep, your eyes move rapidly and your breathing, blood pressure, and heart rate increase. This sleep is when most of your dreaming occurs, so your body is paralyzed to prevent you from acting out your dreams.
However, in people with type 1 narcolepsy, those hypocretin-producing neurons die off, which causes daytime drowsiness and poor control over REM sleep. As a result, the body may experience paralysis and dreamlike hallucinations — typical symptoms of REM — during the day instead of at night.
What causes the hypocretin-producing neurons to die is less understood, but there is evidence that it might be an autoimmune disorder, where your immune system mistakenly attacks your own body.
For example, a 2009 study published in the journal Sleep checked 200 patients with narcolepsy type 1 for antibodies to bacterial infections known to trigger autoimmunity. Patients who started experiencing narcolepsy within the previous three years had high antibody levels for streptococcal bacteria when compared to the control group, suggesting these antibodies may be a trigger for an autoimmune response that kills hypocretin-producing neurons in your body.
Genetics can also play a role in developing type 1 narcolepsy. People with a specific variation of the HLA-DQB1 gene have an increased risk of developing narcolepsy, but it is not understood exactly why. The HLA-DQB1 gene codes for a protein that is part of the HLA complex, which helps the body distinguish between its own proteins and foreign proteins from viruses or bacteria.
Type 2 narcolepsy
Type 2 narcolepsy occurs without cataplexy, and it is not well understood or well studied, says Christopher Murry, D.O., medical director of the Maine Sleep Institute.
Some experts hypothesize that type 2 narcolepsy is caused when the hypocretin-producing neurons are injured, but less severely, leading to less severe symptoms. It's much less common than type 1.
Treatment for narcolepsy
There is no cure for narcolepsy, and it usually does not get better or resolve on its own. However, Murray says there are effective ways to treat and manage the condition.
The most common lifestyle change to manage narcolepsy is controlling your sleep schedule. Specifically, Murry says it is important to control sleep pressure, or that urge you feel to sleep which increases the longer you have been awake.
For people with narcolepsy, baseline sleep pressure is higher, so you should avoid behaviors that will increase sleep pressure, like staying up too late. Murry says small naps throughout the day can also help control your sleep pressure.
Medication
There are also medications that can help treat narcolepsy. Most commonly, stimulants, such as Modafinil or methylphenidate are used to help you stay alert and resist sleep during the day. Doctors might also prescribe sodium oxybate, which is a strong sedative taken at night. It requires setting an alarm and waking up to take the drug during the night.
A 2006 study published in the journal Sleep found that the two drugs may work even better when combined. Researchers looked at 270 adults with narcolepsy who were taking Modafinil. The participants were then either left on Modafinil or given a Modafinil placebo, and given either sodium oxybate or a sodium oxybate placebo.
Over the course of eight weeks, excessive daytime sleepiness was evaluated using a Maintenance of Wakefulness test, or MWT. Researchers had participants recline in a dimly lit, quiet room and try to stay awake for 20 minutes. Participants would then get a 2-hour break before repeating the test a total of four times.
Researchers found that the group taking both placebos fell asleep about three minutes faster, the group taking a Modafinil placebo and sodium oxybate saw no change, and the group taking both Modafinil and sodium oxybate were able to stay awake three minutes longer.
If you're interested in medication to treat your narcolepsy, talk with your doctor about what's right for you. Both Modafinil and sodium oxybate can cause side effects like oversleeping, and you should take them with caution.