Narcolepsy type 2

without cataplexy

Narcolepsy type 2 (NT2) is a long-lasting (chronic) hypersomnia sleep disorder of the brain (neurologic disorder).

NT2: 

  • Affects the brain’s ability to control sleep and wakefulness
  • Causes excessive daytime sleepiness (EDS) — a strong daytime sleepiness or need to sleep during the day, even with enough sleep the night before
  • Is sometimes called narcolepsy without cataplexy (a sudden and temporary episode of muscle weakness, usually triggered by strong emotions)

NT2 is similar to idiopathic hypersomnia (IH) in some ways and to narcolepsy type 1 (NT1) in other ways. Researchers don’t yet know the cause of NT2, but it isn’t caused by the same problem as NT1.

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What are the symptoms of NT2?

The main symptom of NT2 is EDS that lasts for at least 3 months. Sleep patterns may also change, and if you have NT2, you may need 1 or more naps a day. 

Common symptoms include:

  • EDS — Excessive daytime sleepiness
  • Brain fog — Feeling mentally sluggish or fuzzy, confused, forgetful, or unable to focus
  • Needed naps —
    • Usually short and somewhat refreshing (restorative)
    • May be hard or impossible to avoid
  • Disrupted nighttime sleep — 
    • When you wake up many times in a night
    • You may not notice when this happens, but it can make your sleep less restful and you may wake up feeling tired and unrefreshed
    • Your sleep studies may show arousals (wake-ups) from sleep or a high number of shifts (changes) between different stages of sleep
  • Sleep-related hallucinations (or waking dreams) — seeing, hearing, feeling, or smelling something that is not actually there while you are falling asleep or waking up
  • Sleep paralysis — inability to move or speak, which happens while falling asleep or waking up and lasts for a few seconds to minutes 
  • Sleep attacks — Episodes when you fall asleep in places or at times you don’t want to
  • Fatigue —
    • A lack of physical or mental energy
    • Feeling tired or exhausted
  • Severe sleep inertia (or sleep drunkenness), which may last for a few hours —
    • Struggling to wake up fully, often with an overwhelming desire to go back to sleep
    • Feeling disoriented, confused, or irritable
    • Having poor coordination
    • Doing tasks without realizing it
  • Long sleep — Needing at least 11 hours of sleep per 24-hour period (including naps) or more than 9 hours at night (or whenever you sleep the longest)

You don’t need to have all of these symptoms to be diagnosed with NT2, but you’ll have at least some of them.

To learn more about coping with sleep-related hallucinations and paralysis, visit Project Sleep’s web page.

At what age do NT2 symptoms usually start?

Symptoms most often start in a person’s mid-to-late teens. However, they can start at any age. They may start suddenly or develop over time.

Symptoms may:

  • Happen every day, or a few days a week
  • Get worse or better over hours, weeks, months, or years

If you have NT2, you may have times when you can function (do daily activities such as work or school) well or well enough, and other times when you don’t function well at all. Even if you function well at times, your symptoms should be taken seriously.

How do NT2 symptoms compare to IH and NT1 symptoms?

Visit our web page: “Compare symptoms of idiopathic hypersomnia and narcolepsy types 1 and 2.”

How common is NT2?

Researchers estimate that narcolepsy in general (including both NT1 and NT2) happens in 1 in 2,000 people. It’s harder to know how many people have NT2. Researchers have estimated 1 in every 5,000 people to 1 in every 3,000 people have it. Recent U.S. insurance claims data suggest it happens in 1 in every 1,500 people. However, estimates in Europe have been far lower.

What’s it like to have NT2?

NT2 can greatly affect daily life:

  • The amount and timing of needed sleep can limit daily activities.
  • Sleep-related hallucinations and paralysis can be very distressing.
  • NT2 can cause problems with thinking, working, and socializing. People with NT2 may have trouble doing their jobs, staying in school, having romantic relationships, and fully engaging with their friends and loved ones. 

These effects are especially true for people who aren’t taking medicines that work well. But even with medicines, people who have NT2 may struggle with these activities.

Stories from people living with NT2

While almost everyone with NT2 has EDS and brain fog, not everyone has the other symptoms, and they can affect each person differently. Michelle has NT2 overlapping with IH without long sleep time. For Michelle, the hardest thing is struggling with severe brain fog during the day.

Belle has narcolepsy, and the hardest things for her are falling asleep uncontrollably throughout the day and having frightening sleep-related hallucinations.

While almost everyone with NT2 has EDS and brain fog, not everyone has the other symptoms, and they can affect each person differently. Michelle has NT2 overlapping with IH without long sleep time. For Michelle, the hardest thing is struggling with severe brain fog during the day.

2020 October – Michelle Emrich, MD – “A Doctor’s Once Agile Brain Broken by IH” – Video courtesy of Michelle Emrich

Details

Belle has narcolepsy, and the hardest things for her are falling asleep uncontrollably throughout the day and having frightening sleep-related hallucinations.

Find more personal journey stories on: 

How will doctors know if I have NT2?

Doctors will usually:

  1. Ask about your symptoms and medical history, sometimes using questionnaires
  2. Confirm from your history that you’ve had daily EDS for at least 3 months
  3. Do a complete physical exam and medical tests, including sleep studies, to make sure your EDS isn’t caused by something else

Common causes of EDS other than NT2 include: 

Testing for hypersomnia sleep disorders almost always includes a 2-part sleep study:

  1. An overnight sleep study measures several features of sleep and helps rule out other sleep problems such as sleep apnea. 
  2. A daytime nap study called a Multiple Sleep Latency Test (MSLT) measures how long it takes you to fall asleep during 4 or 5 nap opportunities (chances to nap). The MSLT also shows if you have REM sleep within 15 minutes of falling asleep during a nap. Doctors will usually diagnose you with NT2 if you have all of these features:
    • No cataplexy
    • Falling asleep in 8 minutes or less (on average across all your nap opportunities) 
    • Two or more episodes of REM sleep within 15 minutes of falling asleep (including your overnight sleep study)

You may need to prepare during the weeks leading up to your sleep studies, and your doctor may recommend that you change or stop taking specific medicines. Ask for time off from school or work if your symptoms are likely to keep you from being able to function well while you prepare. This may happen if you need to: 

  • Get much more sleep than you usually do
  • Change from a shift work schedule to a normal schedule
  • Stop medicines that are helping your symptoms
    • You may need to slowly taper off some medicines, such as antidepressants, and it may  take longer for you to stop them before your sleep study and then get back up to a dose that works well for you after your sleep study

To learn more, visit our web pages: 

How can doctors tell the difference between NT1 and NT2?

The MSLT results doctors use to diagnose NT1 and NT2 are the same, so the results don’t help show which sleep disorder you have. Your symptoms, especially cataplexy, can help doctors tell the difference. If your diagnosis still isn’t clear, you may need to follow these steps to tell the difference between NT1 and NT2:

  • Have a blood test for HLA-DQB1*06:02. If this blood test is negative, you most likely have NT2. If this test is positive, you may need step 2.
  • Have a spinal tap to check orexin levels in your cerebrospinal fluid (CSF). If your orexin levels are low, you have NT1. If your orexin levels are normal, you most likely have NT2.

If you’re a person of African descent, you may be more likely to have narcolepsy without cataplexy and with low orexin levels. This is the form of NT1 needing these extra tests for correct diagnosis. Read our article “Differences in Hypersomnia Disorder Symptoms Among African Americans.” 

When should my doctor repeat my sleep studies?

  • Only repeat sleep studies if absolutely necessary — for example, if your symptoms have changed a lot and your doctor thinks your diagnosis has also changed. 
  • If your insurer asks for repeat sleep studies, ask your doctor if the test is needed (“medically indicated”). Your doctor can also recommend different testing, which may include actigraphy and a more detailed sleep diary.

What can help my symptoms?

Visit our web pages:

Learn more

Visit our web page for doctors: “Diagnosis, classification, symptoms, and causes of hypersomnias.”

Published Jan. 19, 2024 |
Revised Jan. 30, 2024
Approved by our medical advisory board