Narcolepsy

Narcolepsy is a chronic sleep disorder that occurs when the brain is unable to regulate sleep-wake cycles. This causes excessive and overwhelming daytime sleepiness, even after plenty of nighttime sleep. If you have narcolepsy, you are likely to become drowsy or fall asleep at inappropriate times and places.

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Narcolepsy: overview and types

When your brain is unable to regulate sleep-wake cycles, narcolepsy can result.

A normal sleep cycle takes around 90 minutes and includes four stages. The first two stages are light sleep. The third stage is when deep, restorative sleep happens. The last stage in the cycle is known as REM sleep (rapid eye movement sleep). It is during this stage that we have dreams and low muscle tone.

However, people with narcolepsy enter REM sleep within 15-20 minutes of falling asleep. They skip over the deep, non-REM sleep our bodies need to feel rested. Going without this restorative stage causes excessive and overwhelming daytime sleepiness, even after plenty of nighttime sleep.

If you have narcolepsy, you are likely to become drowsy or fall asleep at inappropriate times and places. These sleep attacks may happen without warning.

Types of narcolepsy

  • Narcolepsy type 1 (NT1) is the more common type. It is characterized by excessive daytime sleepiness as well as cataplexy—a sudden loss of muscle control that often accompanies strong emotions. NT1 is caused by a deficiency in a chemical called hypocretin (orexin) that regulates sleep.
  • Narcolepsy type 2 (NT2) occurs without cataplexy. Most people with NT2 have normal hypocretin levels. Because it is less common, the causes of NT2 are less well understood as NT1.

What are the symptoms of narcolepsy?

Narcolepsy symptoms often differ from person to person.

Common symptoms

  • Automatic behavior. If you have narcolepsy, you may perform routine behaviors without conscious awareness of them, and you may have no memory of performing the activity at all.
  • Cataplexy. This is when you have a sudden loss of muscle control, usually during an emotional reaction (positive or negative). It can range from slight weakness to total collapse. For instance, your knees may buckle when you’re having a good laugh or a hard cry. Cataplexy is associated with narcolepsy type 1. The frequency of attacks can vary widely, from just a few episodes a year to multiple episodes a day.
  • Disrupted sleep. You may wake up multiple times during the night. You may also develop other sleep disorders, like sleep apnea and restless leg syndrome.
  • Excessive daytime sleepiness (EDS). EDS is characterized by persistent sleepiness or struggling to stay awake, regardless of how much nighttime sleep you get. You may also experience a “sleep attack,” or a sudden and intense urge to sleep at inappropriate times during the day. You may even fall asleep without warning during activities. EDS is often the first and most troublesome symptom of narcolepsy.
  • Hallucinations. These are vivid, often scary dreams or sensations that happen while you fall asleep (hypnagogic hallucinations) or waking up (hypnopompic hallucinations). For instance, you might hear someone screaming in your ear, feel like there are bugs nearby or see a stranger standing in your room. Since you are not fully asleep, these hallucinations may feel like reality.
  • Sleep paralysis. This is a temporary inability to move or speak after waking up or as you fall asleep. You may be completely conscious, but have no control over your body.

Related conditions

As you cope with these symptoms, other problems can arise. These include:

  • Depression or emotional dysregulation.
  • Feeling a continual lack of energy.
  • Trouble concentrating and memorizing things.

If you experience these symptoms, be sure to talk with your doctor. They could be signs of narcolepsy or another medical condition.

Narcolepsy causes and risk factors

Type 1 causes

Narcolepsy type 1 (NT1) is caused by the loss of hypocretin neurons. These brain cells produce the sleep chemical hypocretin. Experts suspect that the neurons are lost because of an autoimmune reaction, which is when the body’s defense system mistakenly attacks healthy cells.

Most people with NT1 inherited a gene variation associated with immune function, meaning that this type of narcolepsy is genetic. However, if you have a family history of narcolepsy, your risk of developing the condition is only around 1%.

Environmental factors, including the influenza virus and other viral infections, may also play a role in NT1.

Finally, head injuries or brain infections that damage the hypocretin neurons may also cause NT1.

Type 2 causes

Most narcolepsy type 2 (NT2) patients do not have a hypocretin deficiency. In these patients, brain trauma that affects the brain regions in charge of sleep may cause narcolepsy. Other brain conditions or infections may also cause NT2.

Often, though, the exact cause of narcolepsy type 2 is unknown.

Risk factors

A risk factor is anything that increases your chance of developing a certain condition. Risk factors for narcolepsy include:

  • Age. While narcolepsy can affect people at any age, you are most likely to develop symptoms during childhood, adolescence, or early adulthood (around age 10–30).
  • Brain injury or infection. A traumatic head injury could impact the hypocretin-producing regions of the brain or other structures involved in regulating the sleep-wake cycle. Other conditions that could cause damage or trigger an immune response include:
  • Environmental exposure. Exposure to neurotoxins in construction sites, agriculture, metalworking and other fields of work could trigger an autoimmune response in the brain. Some common viruses, including influenza (the flu), are also associated with narcolepsy.
  • Family history. If someone in your family has narcolepsy, you are more likely to develop the condition yourself. This is because inheriting certain genes can make you more susceptible to NT1 narcolepsy.

How is narcolepsy diagnosed?

Narcolepsy affects around 200,000 Americans. However, because it shares symptoms with other conditions, it is often misdiagnosed or underdiagnosed. This is why it is important to have an expert care team at your side to help you get the right diagnosis and treatment.

Your first step: talk to your provider

If you experience symptoms of narcolepsy, speak with your healthcare provider and give them a detailed list of your symptoms. Your provider will ask you about your family history, medical history and current medications. These will provide some clues as to the underlying cause of your symptoms.

Diagnostic procedures

Your doctor may order the following diagnostic procedures:

  • Sleep diary or sleep records. Your doctor may ask you to keep a detailed record of your sleep in a journal for two weeks. Your doctor may also ask you to wear a device that monitors periods of wakefulness and rest.
  • Polysomnogram (sleep study). These tests are usually done at sleep clinics. You are given a private room and hooked up to specialty recording equipment. These devices monitor and record your breathing, heart rate, oxygen levels, brain activity and movement. The results are then analyzed by a sleep specialist. This test can also diagnose other sleep disorders, like sleep apnea.
  • Multiple sleep latency test (MSLT). This test measures how long it takes for you to fall asleep during the day after you’ve had a full night’s rest. While hooked up to sensors, you will be asked to take several naps on a few different days. A specialist will analyze your sleep patterns, how quickly you fall asleep and how rapidly you enter REM sleep.

Treating narcolepsy

Narcolepsy is a chronic, lifelong condition. There is no cure for it, but symptoms tend to stabilize as you grow older.

Many treatments can help you manage your symptoms and live life to the fullest. Treatment for NT1 and NT2 are usually very similar, but NT2 narcolepsy patients are generally not prescribed medications for cataplexy.

Medications

  • Stimulants. These drugs stimulate the central nervous system to promote wakefulness during the day. Modafinil and armodafinil are usually the first stimulants prescribed, as they tend to be effective and are not usually addictive. Pitolisant is another stimulant that also helps with cataplexy.
  • Selective Serotonin Reuptake Inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs). These medications treat narcolepsy because they suppress REM sleep and can alleviate symptoms like cataplexy, hallucinations and sleep paralysis.
  • Tricyclic antidepressants. This is another group of medications sometimes prescribed to treat cataplexy. However, they tend to cause side effects like lightheadedness.
  • Sodium oxybate. This medication treats excessive daytime sleepiness and the sudden muscle weakness associated with cataplexy. It also helps improve nighttime sleep quality. However, it can interact with other sleep medications and cause serious health problems, so be sure to follow your doctor’s instructions exactly when taking it.

If you have developed other sleep disorders, such as sleep apnea, you may also need other prescription treatments.

Changes to sleep habits and lifestyle

In addition to medication, your doctor may recommend that you develop new sleep and lifestyle habits. These may include:

  • Practice good sleep hygiene. Maintain a regular sleep schedule (even on weekends), shut off electrical devices an hour before sleeping and create a cool, dark sleep environment. These habits can help improve your nighttime sleep quality.
  • Avoid sedatives and alcohol, especially at night. These substances can worsen symptoms.
  • Eat well and exercise. These healthy habits can help prevent obesity and improve sleep quality.
  • Plan short naps. Schedule short, regular naps. These can help you manage your daytime sleepiness and keep you feeling awake and refreshed.
  • Be cautious while driving or working with machinery. People with sleep apnea are more likely to get into car accidents or get injured while working with machinery. Be cautious while doing these activities. Let others know where you are going, nap before a drive and avoid long drives. Always wear safety equipment and consider napping before working in an environment that requires safety precautions.
  • Talk to others and get support. Narcolepsy doesn’t just cause sleepiness; it can cause social isolation and relationship issues. Some people may not understand what you are going through and may shame you for your symptoms. Consider talking to a support group of other people with narcolepsy. You may also want to seek mental health support to deal with issues like depression or social anxiety.

Narcolepsy is a lifelong condition, but it does not have to be a lifelong burden. Finding a care team with the right mix of empathy and expertise is your first step towards taking charge of your life.

References

National Institute of Neurological Disorders and Stroke (NINDS). Narcolepsy Fact Sheet (https://www.ninds.nih.gov/narcolepsy-fact-sheet)

MedlinePlus: National Library of Medicine. Narcolepsy (https://medlineplus.gov/genetics/condition/narcolepsy/)