Overview

Narcolepsy
Narcolepsy

Narcolepsy is a rare long-term brain condition that causes a person to suddenly fall asleep at inappropriate times.

The brain is unable to regulate sleeping and waking patterns normally, which can result in:

  • excessive daytime sleepiness – feeling very drowsy throughout the day and finding it difficult to concentrate and stay awake
  • sleep attacks – falling asleep suddenly and without warning
  • cataplexy – temporary loss of muscle control resulting in weakness and possible collapse, often in response to emotions such as laughter and anger
  • sleep paralysis – a temporary inability to move or speak when waking up or falling asleep
  • excessive dreaming and waking in the night – dreams often come as you fall asleep (hypnogogic hallucinations) or just before or during waking (hypnopompic hallucinations)

Narcolepsy does not cause serious or long-term physical health problems, but it can have a significant impact on daily life and be difficult to cope with emotionally.

Read more about the symptoms of narcolepsy.

What causes narcolepsy?

Narcolepsy is often caused by a lack of the brain chemical hypocretin (also known as orexin), which regulates wakefulness.

The lack of hypocretin is thought to be caused by the immune system mistakenly attacking the cells that produce it or the receptors that allow it to work.

But this does not explain all cases of narcolepsy, and the exact cause of the problem is often unclear.

Things that have been suggested as possible triggers of narcolepsy include:

  • hormonal changes, which can occur during puberty or the menopause
  • major psychological stress
  • an infection, such as swine flu, or the medicine used to vaccinate against it (Pandemrix) 

Read more about the causes of narcolepsy.

Who's affected?

Narcolepsy is a fairly rare condition. It's difficult to know exactly how many people have narcolepsy because many cases are thought to go unreported.

But it's estimated to affect about 30,000 people in the UK.

Men and women are thought to be affected equally by narcolepsy, although some studies have suggested the condition may be more common in men.

The symptoms of narcolepsy often begin during adolescence, although it's usually diagnosed between the ages of 20 and 40.

Diagnosing narcolepsy

See a GP if you think you may have narcolepsy. They may ask about your sleeping habits and any other symptoms you have.

They may also carry out tests to help rule out other conditions that could be causing your excessive daytime sleepiness, such as sleep apnoea, restless legs in bed and kicking during sleep, or an underactive thyroid gland (hypothyroidism).

If necessary, you'll be referred to a specialist in sleep disorders, who'll analyse your sleep patterns.

This will usually involve staying overnight in a specialist sleep centre so various aspects of your sleep can be monitored.

Read more about diagnosing narcolepsy.

Treating narcolepsy

There's currently no cure for narcolepsy, but making changes to improve your sleeping habits and taking medicine can help minimise the impact the condition has on your daily life.

Taking frequent, brief naps evenly spaced throughout the day is one of the best ways to manage excessive daytime drowsiness.

This may be difficult when you're at work or school, but your GP or specialist may be able to devise a sleep schedule that will help you get into a routine of taking naps.

Keeping to a strict bedtime routine can also help, so you should go to bed at the same time each night whenever possible.

If your symptoms are particularly troublesome, you may be prescribed medicine that can help reduce daytime sleepiness, prevent cataplexy attacks and improve your sleep at night.

These medicines are usually taken as daily tablets, capsules or drinkable solutions.

Read more about treating narcolepsy.

National Congenital Anomaly and Rare Diseases Registration Service

If you or your child has narcolepsy, your clinical team will pass information about you or your child on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).

The NCARDRS helps scientists look for better ways to prevent and treat narcolepsy. You can opt out of the register at any time.

Narcolepsy and driving

If you're diagnosed with narcolepsy, it may affect your ability to drive.

Stop driving immediately and inform the Driver and Vehicle Licensing Agency (DVLA).

You'll need to complete a medical questionnaire so your individual circumstances can be assessed.

You'll usually be allowed to drive again if your narcolepsy is well controlled and you have regular reviews to assess your condition.

GOV.UK has more information about narcolepsy and driving.

The Narcolepsy UK website also has more on driving and narcolepsy.

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Symptoms

Not everyone with narcolepsy has the same symptoms. Some people have symptoms regularly, while others are less frequently affected.

Symptoms may develop slowly over a number of years, or suddenly over the course of a few weeks.

Narcolepsy is usually a long-term (chronic) condition, although some of the symptoms may improve as you get older.

You should see a GP if you think you may have narcolepsy so they can find out what's causing your symptoms.

If necessary, you'll be referred to a sleep disorder specialist, who can confirm the diagnosis.

Read more about diagnosing narcolepsy.

Excessive daytime sleepiness

Excessive daytime sleepiness is usually the first sign of narcolepsy. It can have a significant impact on everyday life.

Feeling drowsy throughout the day and struggling to stay awake makes it difficult to concentrate at work or school.

People with narcolepsy may be misjudged as being lazy or rude.

Sleep attacks

Sleep attacks, where you fall asleep suddenly and without warning, are also common in people with narcolepsy. They may happen at any time.

The length of time a sleep attack lasts will vary from person to person. Some people will only have "microsleeps" lasting a few seconds, whereas others may fall asleep for several minutes.

If narcolepsy is not well controlled, sleep attacks may happen several times a day.

Cataplexy

Most people who have narcolepsy also experience cataplexy, which is sudden temporary muscle weakness or loss of muscular control.

Typical symptoms of cataplexy are:

  • the jaw dropping
  • the head slumping down
  • legs collapsing uncontrollably
  • slurred speech 
  • double vision or finding it difficult to focus

Cataplexy attacks are usually triggered by an emotion, such as excitement, laughter, anger or surprise.

Attacks can last from a few seconds to several minutes.

Some people with narcolepsy have cataplexy attacks once or twice a year, while others have them several times a day. 

In an attempt to avoid attacks, some people may become emotionally withdrawn and socially isolated.

Sleep paralysis

Some people with narcolepsy experience episodes of sleep paralysis. This is a temporary inability to move or speak that occurs when waking up or falling asleep.

The episodes can last from a few seconds to several minutes. Although sleep paralysis does not cause any harm, being unable to move can be frightening.

Other symptoms

Narcolepsy can also cause a number of other symptoms, including:

  • hallucinations – seeing or hearing things that are not real, particularly when going to sleep or waking up; a presence in the bedroom is the most commonly reported hallucination
  • memory problems
  • headaches
  • restless sleep – for example, having hot flushes, waking up frequently, having vivid nightmares, or physically acting out dreams
  • automatic behaviour – continuing with an activity without having any recollection of it afterwards
  • depression

Speak to a GP if you have narcolepsy and it's making you feel low or depressed.

They can advise you about how to minimise the effect narcolepsy has on your daily life.

They can also put you in touch with narcolepsy organisations or support groups, such as Narcolepsy UK.

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Causes

Many cases of narcolepsy are thought to be caused by a lack of a brain chemical called hypocretin (also known as orexin), which regulates sleep.

The deficiency is thought to be the result of the immune system mistakenly attacking parts of the brain that produce hypocretin.

But a lack of hypocretin is not the cause in all cases.

Immune system problem

Normally, antibodies are released by the body to destroy disease-carrying organisms and toxins. 

When antibodies mistakenly attack healthy cells and tissue, it's known as an autoimmune response.

In 2010, scientists in Switzerland discovered that some people with narcolepsy produce antibodies against a protein called trib 2.

Trib 2 is produced by an area of the brain that also produces hypocretin. This results in a lack of hypocretin, which means the brain is less able to regulate sleep cycles.

These research results may help explain the cause of narcolepsy in many cases, but it does not explain why some people with the condition still produce near-normal levels of hypocretin.

Possible triggers

A number of factors may increase a person's risk of narcolepsy or cause an autoimmune problem.

These include:

  • an inherited genetic fault
  • hormonal changes, including those that take place during puberty or the menopause
  • major psychological stress
  • a sudden change in sleep patterns
  • an infection, such as swine flu or a streptococcal infection
  • having the flu vaccine Pandemrix

Research is yet to confirm whether all of these play a role in narcolepsy.

Pandemrix vaccine

Research carried out in 2013 found an association between the flu vaccine, Pandemrix, which was used during the swine flu epidemic of 2009-10, and narcolepsy in children.

The risk is very small, with the chance of developing narcolepsy after having a dose of the vaccine estimated to be around 1 in 52,000.

But Pandemrix is no longer used in the UK for flu vaccination.

Impact of narcolepsy on sleep

The total time someone with narcolepsy spends sleeping is not necessarily different from that of people who do not have the condition.

But narcolepsy can significantly affect sleep cycles and decrease the quality of sleep.

Sleep is made up of cycles of different brain activity known as non-rapid eye movement (NREM) and rapid eye movement (REM).

During REM sleep, your brain activity increases and you may dream. Normal sleep starts with 3 stages of NREM sleep at first, followed by a short period of REM sleep.

NREM and REM sleep then alternates throughout the night. During the latter part of the night, REM sleep is more prominent.

If you have narcolepsy, this pattern is much more fragmented and you may wake several times during the night. 

You may also experience REM sleep much earlier than normal after falling asleep, and the effects of REM sleep, such as dreaming and paralysis, while you're still conscious.

Secondary narcolepsy

Narcolepsy can sometimes be the result of an underlying condition that damages the areas of the brain that produce hypocretin.

For example, narcolepsy can develop after:

  • a head injury
  • a brain tumour
  • multiple sclerosis (MS)
  • encephalitis 

Narcolepsy resulting from an identifiable underlying condition is called secondary narcolepsy.

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Diagnosis

Narcolepsy can usually be diagnosed by observing how you sleep and ruling out other conditions.

See a GP if you think you have narcolepsy. Before your appointment, you may find it useful to record your symptoms in a diary or complete an Epworth sleepiness questionnaire.

The GP will look closely at your medical and family history. They'll ask about your sleeping habits and any other symptoms you have.

Ruling out other conditions

Narcolepsy can be difficult to diagnose because the symptoms can be similar to those of other conditions, such as:

Excessive daytime sleepiness can also sometimes be caused by the side effects of certain medicines.

Your GP may carry out several tests to help rule out other conditions that could be causing your symptoms.

For example, you may have a physical examination, blood pressure tests and blood tests.

Sleep analysis

If your GP thinks you may have narcolepsy, they'll refer you to a specialist in sleep disorders, who will analyse your sleep patterns.

There are many different ways your sleep can be analysed.

Epworth sleepiness scale

The Epworth sleepiness scale (PDF, 64kb) is a questionnaire used to assess how likely it is you'll fall asleep while doing different activities.

Your GP will use the results to decide whether to refer you to a sleep specialist.

When filling out the questionnaire, you'll be asked to rank the likelihood that you'll fall asleep in situations such as sitting and reading, watching television and travelling as a passenger in a car.

A score of 10 or below means you have the same level of daytime sleepiness as the general population. If you score 11 or above, you have an increased level of daytime sleepiness.

If this is the case, your GP will probably refer you to a sleep specialist for further investigation.

Polysomnography

Polysomnography is an investigation of your sleep carried out at a specialist sleep centre.

It usually involves staying overnight at the sleep centre so your sleeping patterns can be analysed.

During the night, several different parts of your body will be monitored using electrodes and bands that are placed on your body while you sleep.

Sensors will also be placed on your legs and an oxygen sensor will be attached to your finger.

A number of different tests will be carried out during polysomnography, including:

  • electroencephalography (EEG), which monitors brain waves
  • electrooculography, which monitors eye movements 
  • electromyography (EMG), which monitors muscle tone
  • recordings of movements in your chest and tummy (abdomen)
  • recordings of airflow through your mouth and nose
  • pulse oximetry, which measures your heart rate and blood oxygen levels
  • electrocardiography (ECG), which monitors your heart

 

Sound recording and video equipment may also be used to record sound and images.

After you have slept, a specialist will analyse your test results to determine whether you have normal brain wave activity, breathing patterns, and muscle and eye movement.

Multiple sleep latency test

A multiple sleep latency test measures how long it takes for you to fall asleep during the day. You may have this test after polysomnography.

You'll be asked to take several naps throughout the day, and a specialist will analyse how quickly and easily you fall asleep.

If you have narcolepsy, you'll usually fall asleep easily and enter rapid eye movement (REM) sleep very quickly.

You may also have a blood test to find out whether you have a genetic marker known as HLA DQB * 0602, which is associated with narcolepsy.

A positive result supports a diagnosis, but does not make it 100% certain – 30% of people without narcolepsy also have the genetic marker.

Measuring hypocretin (orexin) levels

Narcolepsy is often linked to a deficiency in the sleep-regulating brain chemical hypocretin, also known as orexin.

Research has shown that measuring the level of hypocretin in your cerebrospinal fluid, which surrounds the brain and spinal cord, can be useful in diagnosing narcolepsy.

To measure your level of hypocretin, a sample of cerebrospinal fluid is removed using a needle during a procedure called a lumbar puncture.

This test is increasingly being used by sleep disorder specialists to help make a diagnosis.

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Treatment

There's no specific cure for narcolepsy, but you can manage the symptoms and minimise their impact on your daily life.

Making some simple changes to your sleeping habits can sometimes help. If your symptoms are more severe, you'll usually need to take medicine.

Good sleeping habits

Things you can do to reduce excessive daytime sleepiness and make it easier to sleep at night include:

  • taking frequent, brief naps – space them evenly throughout the day; your GP or sleep specialist can help you plan a schedule that fits in with your other activities
  • sticking to a strict bedtime routine – aim to go to bed and wake up at the same time every day whenever possible
  • relaxing before going to bed – have a warm bath, for example 
  • ensuring you have a good sleeping environment – for example, keeping your bedroom at a comfortable temperature, quiet and free from distractions
  • avoiding caffeine (found in coffee, tea and some fizzy drinks), alcohol and smoking before going to bed
  • not exercising too close to bedtime – leave at least 2 hours between finishing exercise and going to bed
  • not eating large, heavy meals before going to bed

Some medicines you buy from a pharmacy, such as cold and allergy medicines, can cause drowsiness as a side effect.

You should avoid taking these types of medicines during the day if you have narcolepsy, as they may make your daytime drowsiness worse.

Speak to a GP or pharmacist if you're unsure about which medicines cause drowsiness. They may be able to recommend non-drowsy alternatives.

Talking to others

As well as being a difficult condition to live with, narcolepsy can be difficult for others to understand.

Some of the symptoms, such as sudden loss of muscle control (cataplexy), can be frightening for people who are unaware of the condition.

You may find it useful to talk to your friends and family about your condition.

Tell your child's teachers if your child is diagnosed with narcolepsy. It's important that teachers are aware of your child's condition so they do not mistake their behaviour for laziness or staying up too late at night.

If you have narcolepsy, there's no reason why you should not be able to work, as long as your employer is aware of your condition and agrees to accommodate it, such as allowing you to work flexible hours or take planned naps. But some careers will not be suitable for you.    

Your GP or specialist may be able to arrange for you to speak to a social worker if they think it may help.

A social worker can offer counselling and support, including advice about careers, any adjustments that can be made at school or work, and any financial or relationship problems you may be having.

You might also find it useful to contact a local or national narcolepsy support group, such as Narcolepsy UK.

They'll be able to provide advice about living with narcolepsy and can put you in touch with other people in a similar situation.

Medicine

A number of different medicines are used to treat the symptoms of narcolepsy, but they're not all licensed for narcolepsy and the evidence for their effectiveness in treating the condition is not always strong.

The availability of some of these medicines on the NHS can also differ, depending on the policy of your local NHS authority.

Stimulants

If necessary, your GP or specialist may prescribe a type of medicine known as a stimulant, such as modafinil, dexamphetamine, methylphenidate or pitolisant.

These medicines stimulate your central nervous system, which can help keep you awake during the day. They're usually taken as tablets every morning.

Common side effects of stimulants include:

  • headaches
  • nausea
  • nervousness
  • difficulty sleeping at night (insomnia)
  • stomach aches
  • irritability
  • weight loss

Speak to your GP or specialist if you have persistent or troublesome side effects while taking a stimulant. They may be able to prescribe an alternative medicine.

Modafinil has been linked to irregular heartbeats (arrhythmias) and increases in blood pressure, so you'll need to be regularly monitored during treatment to check for these problems.

Sodium oxybate

Sodium oxybate is a medicine that can improve sudden loss of muscle control and help you sleep at night, which can also reduce daytime sleepiness. But it's not yet funded by the NHS in many areas.

Sodium oxybate is a liquid medicine you drink at night in 2 doses: the first when you get into bed, and the second 2.5 to 4 hours later.

You may need to use an alarm clock to ensure you take the medicine at the right times.

You'll need to take sodium oxybate 2 to 3 hours after having a meal, as food can affect how much of the medicine is absorbed into your body.

Do not drink alcohol while taking sodium oxybate. You should also avoid activities that require mental alertness, such as driving or operating heavy machinery, until at least 6 hours after taking it.

Common side effects of sodium oxybate include:

  • nausea
  • dizziness
  • headaches
  • diarrhoea
  • bedwetting
  • vomiting
  • weight loss
  • blurred vision

Tell your GP or specialist if you're taking sodium oxybate and you have persistent or troublesome side effects.

Antidepressants

Although there's some uncertainty about how effective antidepressants are at treating narcolepsy, they're sometimes used to treat symptoms like sudden loss of muscle control, hallucinations and sleep paralysis.

Many different types of antidepressant medicine have been used to treat people with narcolepsy, including:

  • selective serotonin reuptake inhibitors (SSRIs), such as femoxetine, fluoxetine and citalopram
  • serotonin-noradrenaline reuptake inhibitors (SNRIs), such as venlafaxine
  • tricyclic antidepressants (TCAs), such as imipramine and clomipramine

It's thought these medicines work by altering the levels of certain chemicals in your brain and reducing the amount of dreaming (REM) sleep, which is responsible for many of the symptoms of narcolepsy. 

The side effects you may experience will depend on the specific medicine you're taking, but general side effects of antidepressants can include:

  • feeling agitated, shaky or anxious
  • feeling sick
  • a dry mouth 
  • slight blurring of vision
  • constipation
  • dizziness
  • drowsiness
  • problems sleeping (insomnia)
  • sexual dysfunction, such as erectile dysfunction in men or difficulty achieving orgasm

Most side effects will improve within a few weeks. Speak to your GP or specialist if you have any side effects that are particularly troublesome or persistent.

You should not stop taking antidepressants suddenly as you may have unpleasant withdrawal effects.

If you want to stop taking your medicine, your GP will gradually reduce your dose over the course of a few weeks.

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The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website nhs.uk
Last Updated: 16/10/2019 13:46:22