Narcolepsy without cataplexy, or narcolepsy type 2, is a condition that causes excessive daytime sleepiness. Unlike narcolepsy type 1, it does not cause a sudden loss of muscle tone.

Narcolepsy is a neurological disorder with two subtypes: type 1 and type 2. People with type 1 experience cataplexy, which causes part of the body to become limp.

For example, a person with cataplexy may experience eyelid drooping, being unable to contract certain muscles, or physical collapse, depending on how severe it is.

But people with narcolepsy type 2 do not have this symptom. They may have sudden and intense bouts of sleepiness, but they do not experience changes in how their muscles work. Doctors are not sure what causes type 2.

In this article, we will look more closely at narcolepsy without cataplexy, including the symptoms, diagnosis, and treatment.

Narcolepsy without cataplexy is a neurological condition that causes intense daytime sleepiness and sudden sleep attacks. It is also known as type 2 narcolepsy.

Unlike type 1 narcolepsy, type 2 does not cause a sudden loss of muscle tone. Cataplexy is the medical term for this. Cataplexy involves a person losing the ability to use a muscle temporarily, often in response to strong emotions such as fear, anger, or joy.

Another feature that distinguishes narcolepsy type 2 from type 1 is hypocretin. This is a hormone that regulates wakefulness during the day, and rapid eye movement (REM) sleep at night. People with narcolepsy type 2 usually have typical levels of this hormone, while those with type 1 have low levels.

Narcolepsy is rare, but many doctors believe that it goes undiagnosed in many people who have it.

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The only symptom a person must have to receive a narcolepsy type 2 diagnosis is daily sleep attacks. During these attacks, a person suddenly falls into REM sleep. This is the phase of sleep during which dreams occur.

Some other symptoms a person might notice include:

  • sleep paralysis, which is when a person wakes from sleep but cannot move
  • hallucinations
  • excessive sleepiness during the day
  • fragmented sleep at night or insomnia

Narcolepsy exists on a continuum. Symptoms may be relatively mild or so severe that they interfere with virtually every aspect of functioning. Because narcolepsy causes sudden attacks of sleep, though, most people experience the condition as fairly severe or disruptive.

Narcolepsy is not the only reason people might experience intense sleepiness during the daytime. Some other conditions that may mimic narcolepsy without cataplexy include:

  • inadequate sleep
  • shift work sleep disorder
  • sleep apnea
  • medication-induced sleepiness
  • mental health conditions, such as depression
  • substance misuse
  • a longer daily sleep requirement than is typical, especially when paired with inadequate sleep

If a person is experiencing symptoms that could indicate narcolepsy type 2, a doctor may begin by taking a medical history. They will ask about a person’s symptoms, when they began, and how often they occur.

They may also look at their health records to see what medications they take, or at any preexisting conditions, to see if these could explain the symptoms.

Next, they may ask the person to keep a sleep diary for 2 weeks. According to a 2021 article, a doctor cannot diagnose narcolepsy in someone who is getting less than 6 hours of sleep each night, since sleep deprivation can also cause daytime sleepiness.

If a person is getting more than 6 hours of sleep each night and still has symptoms, the doctor may recommend a polysomnogram (PSG) and multiple sleep latency test (MSLT). A PSG is a sleep study that involves doctors observing someone overnight. This can help rule out other causes of tiredness, such as sleep apnea.

The morning after a PSG, doctors can carry out the MSLT. This involves taking scheduled naps over the course of the day, during which doctors will measure how quickly a person enters REM sleep.

The Diagnostic and Statistical Manual of Mental Disorders, 5th edition states that for a person to receive a narcolepsy diagnosis, they must have at least one of the following symptoms:

  • low or absent hypocretin
  • episodes of cataplexy that occur several times each month
  • REM sleep that begins less than 15 minutes after the beginning of sleep, or two or more periods of sudden REM sleep where it takes 8 minutes or less to fall asleep

Since people with narcolepsy type 2 do not experience cataplexy and often have normal hypocretin, detecting sudden REM sleep using an MSLT is an important step for confirming a diagnosis.

There is no cure for narcolepsy. Instead, treatment focuses on managing symptoms.

In narcolepsy without cataplexy, the main symptom is sudden sleepiness. A number of medications can help a person stay awake. Most doctors recommend trying modafinil (Provigil) or armodafinil first. The second-line treatment is amphetamine-like stimulant drugs, such as methylphenidate.

These drugs are not approved for use in children by the Food and Drug Administration (FDA) due to a lack of evidence for their safety.

In addition to medications, some people with narcolepsy find it helpful to try behavior changes to manage their symptoms. Some strategies include:

  • taking strategic 15–20-minute naps during the day
  • maintaining a consistent sleep schedule at night
  • having a relaxing bedtime routine
  • avoiding bright lights and screens before bed, and keeping them out of the bedroom

During the daytime, people can support their circadian rhythm as much as possible by waking up at the same time each day, getting safe exposure to natural daylight, and staying active.

Accommodations at work and school may be helpful, especially if a person has not yet found treatment that reduces their symptoms.

Narcolepsy type 2 can be challenging to live with. Experiencing intense sleepiness during the day can make it more difficult to work or keep up with other responsibilities. In some situations, it can also pose a health risk. For example, activities such as driving or operating equipment can be dangerous for those who get sudden attacks of sleep.

Living with narcolepsy can require significant adjustments as a result of this. A person may need to avoid certain activities or situations, rely on others for transport, and adapt their work and social life around the times when they feel the most tired.

It is important to have adequate support. This may mean getting help from a doctor who specializes in narcolepsy, but also from friends and family, and if it helps, a therapist or counselor. Mental health support can help someone as they come to terms with their diagnosis and manage the challenges of having a chronic condition.

People should talk with a doctor if they think they have narcolepsy or if they experience:

  • intense daytime sleepiness, regardless of how well they sleep
  • sleep issues such as hallucinations or sleep paralysis
  • loss of voluntary muscle control

People with narcolepsy should contact a doctor if:

  • treatment stops working
  • they develop new or worsening symptoms
  • their medication causes side effects that feel intolerable

Narcolepsy is a neurological condition that can affect many aspects of functioning. It causes intense and overpowering sleepiness, which can occur frequently throughout the day.

Narcolepsy without cataplexy is a subtype, also known as narcolepsy type 2. It means someone experiences sleepiness and other symptoms of narcolepsy, but not cataplexy, which is a sudden loss of muscle tone.

Only a healthcare professional can diagnose and treat narcolepsy. People who worry that they may have this condition should consult a sleep specialist or neurologist.

The right combination of medication and lifestyle changes can help with managing narcolepsy. Social and mental health support is also important.