Woman with narcolepsy type 1 fixing her collar in a bathroom mirror

IT TAKES

knowing that a loss of orexin signaling is the root cause to understand

MY NARCOLEPSY TYPE 1

WHAT IS NARCOLEPSY TYPE 1 (NT1)?

Narcolepsy type 1 is a chronic neurological condition that’s caused by a loss of a brain chemical known as orexin

Orexin (also known as hypocretin) is a key regulator of the sleep-wake cycle, and contributes to other essential functions. The loss of orexin leads to disrupted orexin signaling in your brain, which is also thought to cause an imbalance in energy, cognition, and mood.

A key differentiator of narcolepsy type 1 is cataplexy, a sudden muscle weakness that can be triggered by strong emotional responses, so one minute you can be laughing with friends and the next it can feel like your legs are turning into jelly.

Orexin: A key brain chemical that regulates sleep and wakefulness, while also playing a role in attention, mood, and muscle control

A brain diagram showing orexin pathways relating to sleep and wakefulness, attention, cognition, mood, and muscle tone

Adapted from Toor B, et al. Front Neurol Neurosci. 2021, De Luca R, et al. Nat Commun. 2022, Sakurai T. Nat Rev Neurosci. 2007, and Mahoney CE, et al. Nat Rev Neurosci. 2019.

Depiction is for illustrative purposes.

What are the differences between narcolepsy types 1 and 2?

Narcolepsy Type 1 (NT1)

  • Loss of orexin
  • Cataplexy (sudden muscle weakness that can be triggered by strong emotion) is present. Cataplexy can range from drooping facial muscles to losing balance and falling down
  • About 30% to 35% of US narcolepsy patients
Woman with narcolepsy type 1 sleeping in bed

Narcolepsy Type 2 (NT2)

  • Normal orexin levels
  • People with NT2 do not experience cataplexy
  • Approximately 10% of people with NT2 can later start experiencing cataplexy and progress to NT1
Man with narcolepsy type 1 laying down on a blanket outdoors and throwing a baseball into the air

How orexin works

Orexin binds to receptors in your brain, sending signals that help your body regulate essential functions. When there's a lack of orexin, as seen in people with NT1, this signaling gets disrupted, making it harder for the body to regulate various processes, and in turn making everyday activities more challenging. Let's explore what can be affected when orexin signaling isn’t working properly.

Orexin loss affects:

The sleep-wake cycle

Sleep and wakeful states blend into each other.

A person laying in bed and a clock on the wall icon

Attention

It can be harder to concentrate, remember, and think clearly, which can affect school, work, or daily tasks.

A squiggly line inside a person’s head depicting difficulty with attention icon

Mood

Can affect mood regulation.

A tired person feeling moody icon

Muscle control

It can cause sudden muscle weakness, like cataplexy.

A flexing bicep showing muscle weakness icon
Woman with narcolepsy type 1 sitting on the steps of her front porch and smiling

As I got more educated and further along in my journey after I was diagnosed, I'm like, it isn't my fault. It's something going on with my brain.

—TARA, living with NT1

Stay on top of the latest NT1 resources

More education around the symptoms and science of NT1 and other helpful content, including patient stories, coping strategies, and related resources.

Sign up for updates

Recommended for you

Woman with narcolepsy type 1 posing outdoors while wrapped in a knitted blanket

Living with NT1

See what it takes to live with a chronic neurological condition.

Explore the impact
Brain neurons

NT1 care today

See the different ways people living with NT1 manage their symptoms.

Disease management strategies