What is narcolepsy?

Narcolepsy is a disorder characterized by an excessive daytime sleepiness, sudden weakening of muscles, hallucinations and sleep paralysis.  Most of the time the disorder is unrecognized and the disease is usually diagnosed about 10 years after the onset. Among all people with narcolepsy, 50% will eventually recall that the symptoms began in their teenage years.  Narcolepsy can lead to impaired social and academic performance in otherwise intellectually normal children. Many people may not understand the implications of narcolepsy including parents, teachers, healthcare professionals as well as the people with the condition themselves.

In the United States, around 0.02-0.18% people suffer from narcolepsy. It is more common among people who have close relatives with the same condition. It also affects around 0.02% of the worldwide population. It is slightly more common in males compared to females. It most commonly arises in people aged around 15 years or 36 years.  However, some cases have also been reported in children as young as 2 years of age.

What are the main differences between the normal sleep pattern and narcolepsy?

When you go to sleep, you normally begin by entering a phase known as the non-rapid eye movement sleep (NREM sleep). After around an hour, the brain’s level of activity changes and this is when you enter the Rapid-eye movement (REM) sleep. REM sleep is the phase during which we usually have dreams. However, if you have narcolepsy, you can all of a sudden enter the REM sleep without going through the NREM sleep at any time of the day.

What are the causes and risk factors of narcolepsy?

The exact cause of narcolepsy is currently unknown. However, it is thought to be as a result of genetic predisposition, abnormal functioning of neurotransmitters (chemical substances released in the body to transmit messages in between neurons), or of abnormal immune responses.

Some people with narcolepsy have abnormally low levels of hypocretin which is an important chemical in the brain that helps in the regulation of wakefulness and rapid eye movement sleep. Hypothesis suggests that this decrease in hypocretin is due to an autoimmune reaction. You are also more at risk of having narcolepsy if you have first degree relatives with the same condition, which is in favour of a possible genetic predisposition.

What are the signs and symptoms of narcolepsy?

Narcolepsy is characterized by the following symptoms:

• Excessive daytime sleepiness: As the name suggests, it exceeds normal sleeping pattern or cycles. In normal people, sleepiness usually arises in boring or sedentary situations. However, people with narcolepsy have involuntary sleepiness during activities as important as driving, eating or even talking. It happens in sleeping attacks and occur suddenly.
• Cataplexy: This is the term for a brief and sudden loss of muscle tone. When this happens, it often results in a fall. In more subtle forms, it may only cause a head nod or knee buckling. This symptom is present in around 70% of people with narcolepsy. Cataplexy can also be characterised by slurred speech or maybe triggered by intense emotions such as anger, surprise or fear.

• Sleep disturbances: Some people may experience sleep paralysis.  This is the inability to move upon awakening or sometimes when you fall asleep with intact consciousness. In some people, hallucinations have been reported. Most people with narcolepsy experience sleep disturbances at night.

Other symptoms of narcolepsy include the following:

• Inattentiveness
• Changes in mood
• Obstructive sleep Apnea
• Restless leg
• Insomnia

How is the diagnosis of narcolepsy made?

To make the diagnosis of narcolepsy, your doctor will first start by asking you a series of question to know more about your symptoms. He/she will then proceed by performing a physical examination to look for other signs. There are no blood tests for the diagnosis of narcolepsy. In most cases, the diagnosis is made based on a clear clinical history and a physical examination. You may then be referred to a sleep specialist after a preliminary evaluation.

Sleep studies are generally helpful to confirm the diagnosis of narcolepsy. This requires overnight stay in some cases for a good evaluation. Polysomnography is a procedure in which electrodes are attached to the scalp to monitor the brain’s electrical activity, in combination with other electrodes that simultaneously record the electrical activity of the heart and the movement of the muscles and the eyes. It also includes breathing patterns monitoring.

Multiple sleep latency test is another test that measures the time taken to fall asleep during daytime. Your sleep patterns are also observed during the procedure.

How is narcolepsy managed?

Management of narcolepsy involves both pharmacologic and nonpharmacologic measures.

Nonpharmacologic measures

If you have narcolepsy, it is important that you have a regular sleeping schedule. This involves sleeping 7.5-8 hours per night. Children with narcolepsy should be encouraged to participate in after-school activities and sports. This can be very beneficial and improve symptoms. It may also be helpful to avoid foods that contain a lot of sugars. You may also have scheduled naps during the day.

Pharmacologic treatment

The treatment options for narcolepsy include the following:

• Stimulants: These medications work by stimulating the nervous system to help you stay awake during day time. Some examples include modafinil or armodafinil. These medications are not addictive nor produce highs and lows as opposed to older stimulants. Some rare side effects may include nausea or headache.
• Selective serotonin reuptake inhibitors (SSRIs) or serotonin and norepinephrine reuptake inhibitors (SNRIs): These medications help to suppress the REM sleep phase as well as to reduce the symptoms of sudden loss of muscular tone, hallucinations and sleep paralysis. Some examples include fluoxetine and venlafaxine.
• Sodium oxybate: This medication is very effective for cataplexy. It helps to improve sleep at night and can also help in controlling daytime sleepiness. Some side effects may include nausea, bed-wetting and worsening sleepwalking.

What is the prognosis of narcolepsy?

If proper management and treatment is initiated, you will usually live a near normal and productive personal life as well as at work. If you do not seek medical help and leave the condition untreated, you are more likely to suffer from psychological devastation. Children with narcolepsy tend to perform poorly at school, being ridiculed by friends and being unable to participate in activities of normal childhood. They tend to also have social impairment. When adults have narcolepsy, it can be embarrassing or result in social isolation. They may suffer from interpersonal stress in relationships as well as sexual dysfunction. Sleep attacks can affect work performance, lead to memory problems or personality changes. They may even be falsely accused of illegal drug use.

Nallu, S., 2020. Narcolepsy.

Vendrame M, Havaligi N, Matadeen-Ali C, Adams R, Kothare SV. Narcolepsy in children: a single-center clinical experience. Pediatr Neurol. 2008 May. 38(5):314-20.

Plazzi G, Serra L, Ferri R. Nocturnal aspects of narcolepsy with cataplexy. Sleep Med Rev. 2008 Apr. 12(2):109-28.

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Arlington, VA: American Psychiatric Association; 2013. 372-78.