Narcolepsy
What is narcolepsy?
Narcolepsy is a chronic disorder of excessive daytime sleepiness. It may occur with other symptoms such as cataplexy, sleep paralysis and hallucinations.
People with narcolepsy have excessive sleepiness during the day despite sufficient sleep length overnight. The sleepiness involves difficulty staying awake in passive situations, an irresistible urge to nap and falling asleep at inappropriate times (such as in meetings, classes or cinemas).
Cataplexy occurs with ‘classic’ narcolepsy, now referred to as Narcolepsy Type 1. It involves a sudden loss of muscle power which is set off by strong emotion such as laughter. Cataplexy typically lasts for up to a couple of minutes and the person is both conscious and awake. Cataplexy does not affect breathing. Episodes of cataplexy can involve all muscles of the body (with the person falling over or buckling at the knees) or may only involve some muscle groups (causing head nodding or jaw sagging, for example).
Many people with narcolepsy also experience other symptoms such as sleep paralysis and hallucinations. However, these can also occur in people who do not have narcolepsy. Sleep paralysis typically occurs on waking up and being unable to move for a short period of time. Hallucinations can occur at the beginning of sleep (known as hypnagogic hallucinations) and end of sleep (known as hypnopompic hallucinations). People will ‘see’ images, shapes or shadows around them. They may be confused as to whether they are dreaming or not. Although those with narcolepsy may fall asleep quickly at night, their sleep may be broken.
What causes narcolepsy?
Narcolepsy is linked to a person’s genetic make-up. Sometimes infections (such as streptococcus or influenza) or severe stress can trigger the onset of narcolepsy. It occurs due to the death (from autoimmune activity) of a small group of cells in an area of the brain known as the lateral hypothalamus. These cells normally produce a chemical called hypocretin (also known as orexin). Hypocretin is very important in wakefulness and in keeping the states of being either awake or asleep more stable.
How common is narcolepsy?
Worldwide, it affects about 4 people per 10,000. Both men and women get narcolepsy. It can occur at any age but most commonly develops in the second decade of life, with a smaller peak at around the age of 40.
When to Seek Help from a Sleep Specialist?
Many individuals live with narcolepsy for years before receiving a proper diagnosis. If you find it difficult to stay awake during the day — especially in situations where alertness is expected — and the cause is unclear, it's important to seek specialist care. Symptoms such as excessive daytime sleepiness or sudden loss of muscle control triggered by emotions like laughter or fear (a sign of cataplexy) may indicate a sleep disorder that requires further investigation. For your safety, we strongly advise against driving if you are feeling excessively sleepy or have episodes of sudden sleep.
How does it affect people?
Usually the symptoms of narcolepsy develop slowly over time, although sometimes symptoms start more suddenly. Sleepiness is usually the first symptom, with cataplexy and other features possibly developing later. The sleepiness can make it very hard for people to function normally during the day. Learning, concentration and attention can all be reduced, as can the ability to drive safely. Some people with narcolepsy can also experience depression.
How We Can Help
At our sleep clinic, our experienced sleep and respiratory physicians provide comprehensive evaluation and care. If your symptoms suggest narcolepsy or another sleep disorder, we will conduct a detailed assessment and arrange for diagnostic testing, including an overnight sleep study and a Multiple Sleep Latency Test (MSLT). These tests are performed in a comfortable, professional environment to ensure accurate diagnosis and tailored treatment.
What else might cause the symptoms?
There are many possible reasons why you may be feeling sleepy or tired. In addition to narcolepsy, there are other sleep disorders (such as obstructive sleep apnoea and Idiopathic Hypersomnia) which can also cause sleepiness during the day. Insufficient sleep, depression and other medical conditions can also cause sleepiness
What is the Multiple Sleep Latency Test?
After waking from an overnight sleep study, you will stay in the sleep laboratory until late that afternoon. Every two hours after waking in the morning, you will be asked to return to bed for 20 minutes and try to fall asleep. There will usually be 4-5 of these nap opportunities through the day. During each of the nap opportunities, the time taken to fall asleep and whether any REM sleep occurs are recorded. Falling asleep quickly and experiencing REM sleep during the Multiple Sleep Latency Test are features of narcolepsy.
How is narcolepsy treated?
There is currently no cure for narcolepsy although symptoms may be controlled with medication. Wake-promoting medications are used to control excessive sleepiness and some particular antidepressants can help control other symptoms such as cataplexy and hallucinations.
What could you do to help with symptoms?
It is important to maintain a healthy lifestyle, including minimising alcohol and ensuring enough sleep at night. Planned power naps during the day can reduce sleepiness. Some people with cataplexy are able to ‘flatten’ their emotions to reduce episodes of cataplexy. Driving should be avoided where there is excessive daytime sleepiness or uncontrolled cataplexy. Make family and friends aware of your diagnosis so they can provide support where needed.