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Narcolepsy is a rare long-term brain disorder 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 having difficulty concentrating and staying 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 doesn't 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?
Many cases of narcolepsy are caused by a lack of the brain chemical hypocretin (also known as orexin), which regulates wakefulness.
The lack of hypocretin is thought to occur because the immune system mistakenly attacks the cells that produce it or the receptors that allow it to work.
However, this doesn't 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 medication used to vaccinate against it (Pandermix)
Read more about the causes of narcolepsy.
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.
However, it's estimated the condition affects at least 25,000 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 often begin during adolescence, although the condition is usually diagnosed between the ages of 20 and 40.
Make an appointment to see your 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 will 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.
There's currently no cure for narcolepsy, but making changes to improve your sleeping habits and taking medication 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 medication that can help reduce daytime sleepiness, prevent cataplexy attacks and improve your sleep at night.
These medications are usually taken as daily tablets, capsules or drinkable solutions.
Read more about treating narcolepsy.
Information about you
If you or your child has narcolepsy, your clinical team may pass information about you/them on to the Congenital Anomaly and Register and Information Service (CARIS).
This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.
Find out more about the register.
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.
Not everyone with narcolepsy experiences the same symptoms. Some experience them 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 make an appointment to see your GP if you think you may have narcolepsy so they can determine 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
In most cases, excessive daytime sleepiness is the first sign of narcolepsy. This 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 – falling asleep suddenly and without warning – are also common in people with narcolepsy. They may occur 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 isn't well controlled, sleep attacks may happen several times a day.
Most people who have narcolepsy also experience cataplexy – sudden, temporary muscle weakness or loss of muscular control.
Typical symptoms 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 experience them several times a day. In an attempt to avoid attacks, some people may become emotionally withdrawn and socially isolated.
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 doesn't cause any harm, being unable to move can be frightening.
As well as the symptoms described above, narcolepsy can cause a number of other symptoms, including:
- hallucinations – seeing or hearing things that aren't real, particularly when going to sleep or waking up; a presence in the bedroom is the most commonly reported hallucination
- memory problems
- 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
Speak to your GP if you have narcolepsy and it's making you feel low or depressed.
Your GP can advise you about how to minimise the effect narcolepsy has on your daily life. They can also put you in touch with a narcolepsy organisation or support group.
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Many cases of narcolepsy are thought to be caused by a lack of the brain chemical hypocretin (also known as orexin), which regulates sleep.
This deficiency is thought to result from the immune system mistakenly attacking parts of the brain that produce hypocretin. However, a lack of hypocretin isn't 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 doesn't explain why some people with the condition still produce near-normal levels of hypocretin.
A number of factors may increase a person's risk of narcolepsy or cause an autoimmune problem, including:
Research is yet to confirm whether all of these play a role in narcolepsy.
Recent research has shown an association between the use of the flu vaccine, Pandemrix, which was used during the swine flu epidemic of 2009-10, and narcolepsy in children.
However, the risk is very small. Researchers estimate the chance of developing narcolepsy after receiving a dose of the vaccine is around 1 in 52,000 in the UK.
As a result of the findings, Pandemrix is no longer given to people under the age of 20.
Impact of narcolepsy on sleep
The total time someone with narcolepsy spends sleeping isn't necessarily different from that of people who do not have the condition. However, narcolepsy can significantly affect sleep cycles and decrease the quality of sleep.
Sleep consists of cycles of different brain activity known as non-rapid eye movement (NREM) and rapid eye movement (REM). During REM sleep, brain activity increases and dreaming may occur.
Normal sleep consists of three stages of NREM sleep at first, followed by a short period of REM sleep, with NREM and REM sleep then alternating 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 may experience effects of REM sleep, such as dreaming and paralysis, while you're still conscious.
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Narcolepsy can sometimes occur as a result of an underlying condition that damages the areas of the brain that produce hypocretin.
For example, narcolepsy can sometimes develop after:
Narcolepsy caused by an identifiable underlying condition is known as secondary narcolepsy.
Narcolepsy can usually be diagnosed by observing how you sleep and ruling out other conditions.
If you think you may have narcolepsy, you should see your GP. Before your appointment, it may be useful to record your symptoms in a diary or complete an Epworth sleepiness questionnaire.
Your GP will take a close look at your medical and family history. They will ask about your sleeping habits and any other symptoms you are experiencing.
Ruling out other conditions
Narcolepsy can sometimes be difficult to diagnose because the symptoms may be attributed to other conditions, such as sleep apnoea, epilepsy, depression, an underactive thyroid gland (hypothyroidism), or a previous head injury.
Excessive daytime sleepiness can also sometimes be caused by the side effects of certain medications.
Your GP may therefore carry out several tests to try to rule out any other conditions that may be causing your symptoms. For example, you may have a physical examination, blood pressure tests, and blood tests.
If your GP thinks you may have narcolepsy, they will 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 you are to fall asleep while undertaking different activities. Your GP will use the results of your completed questionnaire to decide whether to refer you to a sleep specialist.
When you fill out the questionnaire, you will be asked to rank the likelihood that you will 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 indicates you have a level of daytime sleepiness equal to the general population. A score of 11 or above indicates 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 is an investigation of your sleep carried out at a specialist sleep centre. The study 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 carefully monitored using electrodes and bands that are placed on the surface of your body while you sleep. Sensors will also be placed on your legs and an oxygen sensor is 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 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 will 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 will 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 doesn't make it 100% certain – 30% of people without narcolepsy also have the genetic marker.
Measuring hypocretin (orexin) levels
Many cases of narcolepsy are linked to a deficiency in the sleep-regulating brain chemical hypocretin, also known as orexin.
Recent 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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The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
There's no specific cure for narcolepsy, but you can manage the symptoms and minimise their impact on your daily life.
In mild cases, making some simple changes to your sleeping habits can help. If the symptoms are more severe, you'll usually need to take medication.
Good sleeping habits
There are steps you can take to reduce excessive daytime sleepiness and make it easier to sleep at night. These 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
- 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 two hours between finishing exercise and going to bed
- not eating large, heavy meals before going to bed
Some over-the-counter medications, 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 your 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 also 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.
Inform your child's teachers if your child is diagnosed with narcolepsy. It's important that teachers are aware of your child's diagnosis so they don't mistake their behaviour for laziness or staying up too late at night.
If you’re diagnosed with narcolepsy there’s no reason why you shouldn’t be able to work, as long as your employer is aware of your diagnosis and they agree to an approach that accommodates your sleep disorder, such as flexible working hours or allowing you to take planned naps. Some careers, however, won’t 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. They'll be able to provide advice about living with narcolepsy and can put you in touch with other people in a similar situation.
A number of different medications are used to treat the symptoms of narcolepsy, although they're not all licensed for narcolepsy and the evidence for their effectiveness in treating the condition isn't always strong.
The availability of some of these medications on the NHS can also differ, depending on the policy of your local NHS authority.
If necessary, your GP or specialist may prescribe a type of medicine known as a stimulant, such as modafinil, dexamphetamine or methylphenidate.
These medications 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:
- difficulty sleeping at night (insomnia)
- stomach aches
- weight loss
Speak to your GP or specialist if you experience 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 is a medicine that can improve cataplexy and help you sleep at night, which can also reduce daytime sleepiness. However, it's not yet funded by the NHS in many areas.
Sodium oxybate is a liquid medicine that you drink at night in two 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 the drug two to three hours after having a meal as food can affect the amount of medication absorbed into your body.
You should avoid drinking alcohol while taking sodium oxybate. You should also avoid activities that require mental alertness, such as driving or operating heavy machinery, until at least six hours after taking it.
Common side effects of sodium oxybate include:
Tell your GP or specialist if you're taking sodium oxybate and you experience persistent or troublesome side effects.
Although there's some uncertainty about how effective antidepressants are at treating narcolepsy, they're sometimes used to treat symptoms such as cataplexy, hallucinations and sleep paralysis.
Many different types of antidepressant medication 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
These medications are thought to 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 medication you're taking, but general side effects of antidepressants can include:
Most side effects will improve within a few weeks. Speak to your GP or specialist if you're experiencing any side effects that are particularly troublesome or persistent.
You shouldn't stop taking antidepressants suddenly as you may experience unpleasant withdrawal effects. If you want to stop taking your medication, your GP will reduce your dose gradually over the course of a few weeks.
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Last Updated: 13/06/2016 11:39:13