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Published on: 7/15/2026

What are the different types of narcolepsy and how are they classified?

Yoshinori Abe

Reviewed by Yoshinori Abe, MD

Internal Medicine

Narcolepsy is a chronic neurological sleep disorder that causes excessive daytime sleepiness (EDS), and it is classified into two main types:

  • Narcolepsy Type 1 (NT1): Involves excessive daytime sleepiness plus cataplexy — sudden episodes of muscle weakness triggered by strong emotions while awake. NT1 is linked to low levels of hypocretin, a brain chemical that regulates wakefulness.
  • Narcolepsy Type 2 (NT2): Involves excessive daytime sleepiness without cataplexy. Hypocretin levels typically remain normal, and symptoms are often milder.

Both types can significantly impact daily life, but they require different diagnostic and treatment approaches.

If you're experiencing persistent daytime sleepiness, sudden muscle weakness, or other unexplained symptoms, understanding the possible cause is the critical first step. Rather than guessing — or waiting weeks for a specialist appointment — you can take a free, instant, online symptom check to explore what might be going on and get clear guidance on next steps. It takes only a few minutes and could help you have a more informed conversation with your doctor.

Reviewed for medical accuracy: 07/14/2026

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Important Next Steps

Discover if your sleepiness suggests narcolepsyLearn what’s causing your daytime sleep attacksSee if your symptoms fit narcolepsy typeFind OTC options for sleepiness reliefFind a sleep specialist for narcolepsy careDiscover safe home remedies for narcolepsy symptomsUnderstand if your symptoms need urgent care

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Explanation

Narcolepsy is a disorder that makes people very sleepy during the day. There are two types of narcolepsy, Type 1 and Type 2.

Narcolepsy Type 1: This type is characterized by excessive daytime sleepiness and cataplexy (which is a sudden loss of muscle control while awake, often triggered by strong emotions like laughter, joy, surprise, or anger). People with narcolepsy type 1 also have low levels of a brain chemical called hypocretin, which helps regulate wakefulness.

Narcolepsy Type 2: People with narcolepsy type 2 also experience excessive daytime sleepiness, but they do not have cataplexy.

Both types can cause people to fall asleep suddenly, even during the day. Scientists believe genetics play a role in narcolepsy, which means it can run in families. If you're experiencing excessive daytime sleepiness or other unusual symptoms, you can use a free symptom checker to help identify potential causes and determine if you should speak with a healthcare provider for proper diagnosis and management.

(References)

  • Bassetti CLA, Adamantidis A, Burdakov D, Han F, Gay S, Kallweit U, et al. (2019). Narcolepsy - clinical spectrum, aetiopathophysiology, .... Nature reviews. Neurology, 31324898.

  • Miyagawa T, & Tokunaga K. (2019). Genetics of narcolepsy. Human genome variation, 30652006.

  • Monaca C, Franco P, Philip P, & Dauvilliers Y. (2017). French consensus. Type 1 and type 2 Narcolepsy. Revue neurologique, 27838095.

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