Narcolepsy

Published by Bupa's Health Information Team, June 2011.

This factsheet is for people who have narcolepsy, or who would like information about it.

Narcolepsy is a sleep disorder that interferes with the brain’s sleep cycle and causes people to feel so sleepy that they fall asleep during the day, even during activities.

Some people with narcolepsy also have cataplexy. This is when strong emotion, such as laughter, causes sudden loss of muscle tone.

About narcolepsy

Narcolepsy causes you to have attacks of overwhelming sleepiness. People who have narcolepsy will find themselves feeling very sleepy in the daytime, and may fall asleep at inappropriate times, during meals, while talking or at work for example. Narcolepsy affects between four and five in every 10,000 people in the UK. It is slightly more common in men than women.

Around two-thirds of all people with narcolepsy also have cataplexy. This is when your muscles suddenly lose strength.

Narcolepsy usually starts when you are a teenager, but it often takes a decade or more before it is properly diagnosed. Narcolepsy can be embarrassing in social situations, and it may also affect your academic and job performance. It does not usually run in families.

Symptoms of narcolepsy

The main symptoms of narcolepsy are listed below.

Excessive daytime sleepiness

This is more than just feeling tired because of a poor night's sleep. You may feel sleepy throughout the day and get attacks of overwhelming sleepiness that you can’t fight. These cause you to fall asleep during the day. Sleep attacks are more common if you are doing something boring and repetitive but they can also happen at more inappropriate times such as while eating, or even while driving. You may have several sleep attacks a day and they tend to last from a few minutes to an hour.

Cataplexy

This is a sudden loss of strength in your muscles, triggered by strong emotions such as laughter, anger or excitement. The severity varies between people and depends on which of your muscles are affected. You may just get weakness in your facial muscles, but you may completely collapse if your legs become weak. The attacks are short – lasting from a few seconds up to a couple of minutes – and can happen repeatedly for up to an hour. You remain conscious and aware of what is happening during an attack of cataplexy. You may get cataplexy before or after symptoms of narcolepsy.

Other symptoms

As well as the main symptoms of sleepiness and cataplexy, there are a number of other symptoms that you may get.

• Sleep paralysis. This means waking up in the middle of the night and not being able to move for a couple of minutes. This can be very frightening and can occasionally occur while going to sleep.
• Sleep-related hallucinations. These are vivid dream-like hallucinations that happen while falling asleep or waking up. They may happen at the same time as sleep paralysis.
• Disturbed night-time sleep, including sleepwalking.

Complications of narcolepsy

Narcolepsy can affect your life, having an impact on your education, employment, relationships, your ability to drive and your mood. But with proper management and treatment, people with narcolepsy can have meaningful and productive lives.

Other people may not always understand or accept that attacks of sleepiness are outside your control. If you have narcolepsy, you may find it helpful to be in contact with other people who have it.

Causes of narcolepsy

The exact reasons why you may develop narcolepsy aren't fully understood at present.

People who have narcolepsy seem to have different sleep patterns than usual. Everyone generally has periods of sleep in which they dream, known as rapid eye movement (REM) sleep. During REM sleep, your brain relaxes your muscles to prevent you from acting out these dreams. If you have narcolepsy, your brain is unable to regulate REM sleep. Many of the symptoms of narcolepsy and cataplexy are caused by REM sleep occurring while you're awake. In sleep paralysis, for example, you partially wake during REM sleep and hallucinations are dreams that you experience while awake.

It's thought that a hormone in your brain, known as orexin (or hypocretin) may be involved in narcolepsy. This hormone controls your sleep pattern and how awake you feel. Research has suggested that people who have narcolepsy with cataplexy have low levels of this hormone, so their sleep-wake cycle isn't well controlled.

Low orexin levels are unlikely to be the only cause of narcolepsy as people who have narcolepsy without cataplexy often have normal orexin levels.

There may be a genetic link with narcolepsy that raises your risk of getting the condition and can be inherited. If you have a close relative who has narcolepsy, your risk of having it is estimated to be between 10 and 40 times higher than the general population. However, people without narcolepsy can also carry this genetic marker, so having it doesn’t cause narcolepsy in everyone.

Diagnosis of narcolepsy

It can take several years to get a firm diagnosis of narcolepsy. If you think you have narcolepsy, see your GP. He or she will ask you about your symptoms and how long you have been getting them. If your GP thinks you might have narcolepsy, you may be referred to a sleep clinic.

Sleep clinics specialise in diagnosing sleep disorders. Getting tested at the clinic can tell you whether your daytime sleepiness is down to narcolepsy by ruling out other sleep disorders, such as obstructive sleep apnoea.

You may be asked to stay overnight so that your brain waves, eye movements and breathing can be monitored while you sleep. If you have narcolepsy you tend to fall asleep very quickly. Passing quickly or immediately into the REM phase of sleep also suggests that you have narcolepsy.

The doctor at the sleep clinic may take a blood sample from you for testing. In some clinics, the doctor may also take a sample of fluid from your spine to check your levels of orexin. This is usually only done for research purposes.

Treatment of narcolepsy

There is no cure for narcolepsy. However, treatments are available that can help to manage your symptoms. With good treatment and support, it is possible to be successful at school and in the workplace.

Self-help

There are some lifestyle changes you may be able to make that can help your symptoms.

Sticking to a regular sleep routine may help to limit your sleepiness during the day. There is some evidence to suggest that having a planned nap during the day may help you perform better and relieve sleepiness.

Some doctors think that avoiding sugary foods or drinks may reduce your daytime sleepiness. Avoiding alcohol, heavy meals, and caffeinated drinks in the afternoon may also help.

Medicines

Medicines can be used to help treat some of the symptoms of narcolepsy.

Modafinil

Your GP may prescribe you a medicine called modafinil. It's not clear exactly how this medicine works but it helps you feel awake. Modafinil doesn't keep you awake at night, but it can cause headaches and nausea as side-effects. It also interferes with the contraceptive pill, so if you're taking this, get advice from your GP.

Amphetamines

Your GP may suggest stimulants such as dexamphetamine sulphate, amphetamine and methylphenidate to prevent daytime sleepiness. They work by stimulating the central nervous system. Dexamphetamine sulphate is the most commonly used amphetamine. These medicines can cause side-effects such as making you feel irritable, nervous or aggressive, upsetting your stomach and causing hallucinations. They can also disturb your sleep at night.

Sodium oxybate

You take this medicine at night to help you sleep better. It helps you stay awake during the day and also treats cataplexy. The side-effects of this medicine include loss of appetite, dry mouth, nervousness and constipation.

Antidepressants

Antidepressants are used to treat cataplexy and can reduce sleep paralysis and sleep-related hallucinations. These medicines include selective serotonin reuptake inhibitors, tricyclic antidepressants and noradrenaline reuptake inhibitors.

Living with narcolepsy

You should inform your employer of your condition. If your child is affected, tell his or her school. Make sure they are given enough information to understand the condition.

It can help to contact others who are affected by narcolepsy.

For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.