Narcolepsy

What is narcolepsy?

Narcolepsy is a chronic sleep disorder that has a typical onset in adolescence. The signs of narcolepsy are excessive daytime sleepiness (EDS), sleep paralysis and sometimes cataplexy.

Imagine you could fall asleep anytime, anywhere, with no prior warning. This would be any and every day, not just the ones, where you've had poor sleep.

You could for instance fall asleep:

During the interview for your dream job.
During lectures in your education.
While dating the person you hope to share your life with.
At a very important business meeting.
While driving your car.
While talking to a friend.
While having sexual intercourse.

This would be your reality, if you suffered from narcolepsy. I trust you would find it very hard to live a fully functional life, under these conditions.

It's easy to understand,that this sleep disorder, have severe consequences for the patients. They often face problems like:

social stigma
difficulties in obtaining an education
difficulties in keeping a job
reduced quality of life

Fortunately narcolepsy is a rare sleep disorder. It's estimated to affect 1 in 2000 people.

The 2 types of narcolepsy

There are two types of narcolepsy. They have similar clinical profiles. The only difference between them is the presence of cataplexy, which is a sudden loss of muscle tone.

Narcolepsy type 1 - narcolepsy with cataplexy

Cataplexy is a sudden loss of muscle control, which is often triggered by strong emotion. This comes forward as anything from slurred speech to complete weakness of most muscles. Some experience this several times a day, while others may only experience it once a year.

Cataplexy can be a total or partial body paralysis of the REM sleep, but without being asleep. An unexpected sound or event can cause the patients to collapse - and caught in the prison of their own body. And they are fully awake and conscious, when it happens.

Narcolepsy type 2 - narcolepsy without cataplexy

Victims of this type, still experience excessive daytime sleepiness. They usually don't suffer from the emotion triggered loss of muscle tone. They usually have normal levels of the brain hormone hypocretin, and generally have less severe symptoms.

Causes for narcolepsy type 1 (with cataplexy)

In 1999, Scientists discovered, that narcoleptic subjects lack hypocretin (also called orexin).

The latest scientific research suggests that narcolepsy is an autoimmune sleep disorder. However, direct evidence in support of the autoimmune hypothesis is currently unavailable. Autoimmune means, that the victims own immune system destroys otherwise healthy brain cells.

These destroyed brain cells (called neurons in science lingo), produces the hormone hypocretin. Hypocretin (also called orexin) helps you control your level of wakefulness. That's why the loss of hypocretin/orexin producing neurons, causes narcolepsy.

These brain cells can never be recreated. This means that narcolepsy is a chronic, autoimmune condition. This irreparable destruction of brain cells often happens in the victims early teens.

Narcolepsy symptoms

There are 3 core symptoms for this sleep disorder:

Excessive daytime sleepiness
Cataplexy
Sleep paralysis

Excessive daytime sleepiness

We all have days, where we are more tired than usual. That's not the kind of tiredness, in question here. When you suffer from narcolepsy, your daytime drowsiness is like, if you have not slept at all for 3 - 4 days straight. Hence, the word 'excessive'.

Imagine feeling like that! All the time! Every day! Would make you wish, you only suffered a really bad jet lag.

Narcolepsy and sleep apnea are the 2 most common causes of excessive daytime sleepiness (EDS).

Cataplexy

Sleep Paralysis

Many victims also experience hallucinations or dreams, while they are actually awake. They often have a very realistic sense of an intruder present in their bedroom. That could be a person, an alien or e.g. a ghost. Yet they are unable to move or scream because of the sleep paralysis.

This happens either while they are falling asleep, or when they have just woken up. Some victims say, you learn to live with this.

The experience is closely related to REM sleep, where most of your dreams happen. In the REM sleep stage, most of your muscles can not move.

Narcolepsy puts its victims in a state similar to when you're dreaming in your REM sleep. Yet they are actually awake the whole time. When they do get to sleep, victims of narcolepsy enters the REM sleep stage faster than others.

Note: waking up once without the ability to move, does not automatically mean, that you suffer from narcolepsy. The experience is not unique to narcolepsy. It can happen to anyone.

If you kept a human or an animal awake for more than 24 hours, then it would spend more time in the deep sleep stage. But if you keep a rat awake for a longer period (up to 10 days), it would almost only sleep REM sleep.

This indicates how sleep deprived narcoleptic victims are, as they go to REM sleep so fast.

Narcolepsy diagnosis

Today a diagnosis of narcolepsy is based on clarifying EDS through:

history
subjective evaluation using questionnaires
objective measurement, including nocturnal polysomnography followed by a daytime multiple sleep latency test.

Often it's not diagnosed correctly. Scientists agree that simpler and faster procedures for diagnosing narcolepsy are needed.

There are discussions about the limitations of the current diagnostic criteria for narcolepsy. Recent discoveries lead to establishment of a new diagnostic test for narcolepsy. These tests include test for i.e. low hypocretin levels in the cerebrospinal fluid.

Also, greater awareness of the disorder promotes accurate and efficient diagnosis.

Narcolepsy treatment

As stated above, narcolepsy is a chronic sleep disorder. There is no known cure that can heal it. The destroyed brain cells are irrecoverable with today's tools. To date, no treatment hinders or slows disease development.

Current narcolepsy treatment aims to:

reduce EDS (Excessive Daytime Sleepiness)
reduce cataplexy
improve nighttime sleep disturbance
reduce amount of sleep paralysis
reduce amount of sleep-related hallucinations.

Several medications are available for the treatment of narcolepsy. They all have quite good efficacy and safety profiles.

Medication and lifestyle changes can help you cope with and manage the symptoms. With appropriate treatment, its symptoms are manageable. You can still enjoy a satisfying personal, social, and professional life.

The latest 20 years have seen an explosion in our understanding of narcolepsy. This is fueling new approaches to potentially effective treatments. With ongoing research, better treatments for narcolepsy will inevitably become available.

Drug treatments remain symptomatic. They may soon become more focused on restoring central hypocretin signaling. This is pursued with so called hypocretin replacement therapy.

Hypocretin replacement therapy may be a promising new therapeutic option. There are ongoing experiments using gene therapy and cell transplantation.

Narcolepsy FAQ:

Is narcolepsy genetic?
The genetic cause for narcolepsy appears to be a mutation. Mutations does not explain all incidences of narcolepsy.

Is narcolepsy a disability?
Narcolepsy isn't typically considered a disability. But if your symptoms interfere with your ability to do your job, you may still qualify for benefits. Rules are different in different countries.

Is narcolepsy hereditary?
There seems to be some genetic basis, but it is not inherited.

Is narcolepsy a neurological disorder?
Yes - it is. It's origins are within the brain, which is very much part of the central nervous system.

Is narcolepsy an autoimmune disease?
Narcolepsy is a disease. Narcolepsy type 1 appears to be an autoimmune disease.

Is narcolepsy curable?
The destroyed neurons are irreplaceable, so there is no cure. There are however, various ways to learn to lessen the disadvantages.

Is narcolepsy a mental illness?
No, narcolepsy is not a mental illness. It does, however, carry a high risk for development of social and occupational dysfunction.

Is narcolepsy dangerous?
Sleep deprivation is never healthy, but you will not die directly from narcolepsy. You may get killed e.g. if falling asleep while driving, or crossing the road.

References:

https://pubmed.ncbi.nlm.nih.gov/30546103/
https://pubmed.ncbi.nlm.nih.gov/30526757/
https://pubmed.ncbi.nlm.nih.gov/26716917/
https://pubmed.ncbi.nlm.nih.gov/31324898/
https://pubmed.ncbi.nlm.nih.gov/19555382/
https://pubmed.ncbi.nlm.nih.gov/28179647/
https://pubmed.ncbi.nlm.nih.gov/28991006/
https://pubmed.ncbi.nlm.nih.gov/32985153/
https://pubmed.ncbi.nlm.nih.gov/31004212/
https://pubmed.ncbi.nlm.nih.gov/28778231/