What Is Narcolepsy?

Narcolepsy is a sleep disorder that is characterized by chronic, excessive daytime sleepiness. It is a neurological condition that impacts the brain's ability to manage the sleep-wake cycle. People who have this condition usually have a difficult time staying awake for extended periods of time, no matter what time it is or what they are doing.

The condition can have a significant and serious impact on daily activities since people will feel overwhelmingly tired and unable to stay awake during the day. They may even unwillingly fall asleep in the middle of activities including driving or eating.

Narcolepsy affects approximately 1, in 2,000 people, although the condition is often believed to go underdiagnosed and undertreated.

Narcolepsy Symptoms

There are a number of symptoms that characterize narcolepsy. These include:

Excessive Daytime Sleepiness

When a person has this condition, they will experience a feeling of extreme sleepiness that causes them to fall asleep suddenly without warning. This can happen anywhere at any time. This means that a person could fall asleep in the middle of a conversation, while working, or driving.

In addition to these sudden sleep attacks, people can also have trouble concentrating or staying alert at times throughout the day. This is the primary symptom of the condition and it is often the first to appear.

Sleep Paralysis

When falling asleep or waking, people with narcolepsy may find themselves temporarily unable to move or speak. Such paralysis is usually brief and can last from a matter of a few seconds to several minutes. It can be frightening, but once an episode is over people recover their ability to move and speak. 

Hallucinations

People with narcolepsy may also experience very vivid sensory hallucinations that sometimes can be quite frightening. There are two different types of hallucinations that people may experience:

• Hypnagogic hallucinations occur as people are falling asleep
• Hypnopompic hallucinations occur as people are waking

Cataplexy

Cataplexy is a sudden, uncontrollable loss of muscle tone that affects the neck, face, and knees. It can be triggered by intense positive and negative emotions and can vary in severity from mild to more severe. In some cases, people may only experience mild weakness that causes their head or jaw to drop. In other cases, their knees may buckle and they may collapse to the ground.

Changes In REM Sleep

Rapid eye movement (REM) sleep is a phase during which people experience rapid movements of the eyes, low muscle tone through the body, and a tendency to dream. People who have narcolepsy can enter REM sleep quite quickly after falling asleep and may experience this type of sleep at any time of day.

According to the National Institute of Neurological Disorders and Stroke, symptoms of narcolepsy tend to grow worse over the first two or three decades after their first onset. However, people sometimes find that symptoms of daytime sleepiness become less severe after age 60.

Diagnosis

Your doctor may suspect narcolepsy based if you are primarily experiencing excessive daytime sleepiness and sudden loss of muscle tone. If your doctor thinks you might have narcolepsy, you will then be referred to a sleep specialist to be evaluated further.

In order to diagnose narcolepsy, your doctor will need to perform a physical exam, take a detailed medical history, and conduct sleep studies. Your doctor will ask you detailed questions about your sleep and your level of sleepiness will be rated using a special scale.

Doctors also utilize two types of specialized test to diagnose narcolepsy:

• Polysomnogram (PSG): This test involves placing electrodes on your scalp and looking at the electrical activity in your brain, muscles, and heart. Doctors also look at your breathing so that they can better understand the changes that are happening in your body while you are sleeping. The PSG test can help doctors determine if REM sleep is occurring early on in the sleep cycle—a key characteristic of narcolepsy.
• Multiple sleep latency test (MSLT): This test is conducted during the day following the polysomnogram. For this test, you'll be asked to take four or five naps spaced two hours apart during the day. The MSLT is designed to look at how quickly people fall asleep and how soon they enter REM sleep.

People who fall asleep in less than an average of eight minutes are classified as having excessive daytime sleepiness. What distinguishes normal sleepiness from narcolepsy, however, is the tendency to enter REM sleep abnormally fast. If people begin REM sleep within 15 minutes during at least two of the daytime naps, they most likely have narcolepsy.

As part of your diagnosis, you may also be asked to wear a wrist sensor called an actigraph and keep a sleep diary for a few weeks. In your diary, you'll record how many hours of sleep you get, how easy it is to fall asleep, how easy it is to stay asleep, and how wakeful you feel during the day.

Your doctor will also use this information to help rule out other conditions that might be causing your symptoms. Other sleep disorders such as sleep apnea can also lead to sleepiness during the daytime.

Causes of Narcolepsy

The exact causes of narcolepsy are not known, but there are some factors that are believed to play a role in the development of the condition. 

One explanation for narcolepsy lies in the loss of a specific neurotransmitter called hypocretin. This chemical messenger plays an important role in regulating the sleep/wake cycle and plays a part in REM sleep.

“In narcolepsy, the cluster of cells that produce hypocretin—located in a region called the hypothalamus—is damaged or completely destroyed. Without hypocretin, the person has trouble staying awake, and also experiences disruptions in the normal sleep-wake cycles,” explains The National Sleep Foundation.

The exact reasons for the loss of hypocretin are not fully understood, but researchers believe that it may be caused by autoimmune issues. Due to a combination of genetic and environmental causes, the body's immune system is triggered to attack cells that contain this important chemical messenger.

Other Possible Causes

However, there are also other factors that may contribute to the onset of narcolepsy. These include:

• Autoimmune disorders: Some autoimmune conditions can cause the body to attack certain brain cells, leading to a lack of hypocretin.
• Brain injury, infection, or tumor: If the area of the brain that regulates the sleep cycle is damaged or affected by a tumor, it can lead to problems with REM sleep.
• Environmental toxins: Heavy metals, pesticides, and other toxins can also affect the brain and interrupt the brain’s ability to control the normal sleep/wake cycle.
• Family history: Sometimes people with narcolepsy will also have close family members who also have the same condition.

Researchers have found that people with narcolepsy have changes in the T cell receptor gene (a type of specialized immune cell) that may cause a genetic predisposition to develop the condition.

Types

There are two different types of narcolepsy. They are identified by the presence or absence of specific symptoms.

• Type 1 Narcolepsy: This form was previously referred to as narcolepsy with cataplexy. People who have this type experience excessive daytime sleepiness along with cataplexy. They may also have low levels of the neurotransmitter hypocretin in their brain.
• Type 2 Narcolepsy: This form was previously referred to as narcolepsy without cataplexy. People with this type experience excessive daytime sleepiness and do not have symptoms of cataplexy. They also have normal levels of hypocretin.

There is also a condition known as secondary narcolepsy that can occur if the hypothalamus is damaged. The hypothalamus is located deep inside the brain and is important in the regulation of sleep. Damage to this area can lead to narcolepsy symptoms along with other neurological problems.

Treatment for Narcolepsy

There is no cure for narcolepsy and any associated loss of hypocretin is believed to be irreversible. However, many symptoms of the condition can be managed with the use of medications and lifestyle changes. 

Medications

Some of the medications that may be used to manage the symptoms of narcolepsy include:

• Wakefulness-promoting drugs: Modafinil (Provigil) or armodafinil (Nuvigil) are central nervous stimulants that are usually prescribed as first-line treatments. These drugs are used to help improve alertness levels during the day. These medications are preferred because they are less addictive than many older stimulants. 
• Sodium oxybate: Also known as gamma hydroxybutyrate or GHB, sodium oxybate is FDA approved for the treatment of narcolepsy. It helps reduce symptoms of excessive daytime sleepiness and cataplexy. It is high in sodium, so people who are taking this medication are advised to limit their dietary salt intake.
• Antidepressants: Some symptoms of narcolepsy may also be relieved with the use of certain types of antidepressants. Tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs) may help with cataplexy, hallucinations, sleep paralysis, and disrupted nighttime sleep. SSRIs may be preferred because they tend to have fewer side effects than TCAs. While these medications may be used off-label for this purpose, they have not been FDA approved to treat narcolepsy.
• Other stimulants: While used less frequently than they were in the past, other types of stimulants are sometimes still used as wakefulness-promoting agents. These amphetamine-like medications are carefully monitored due to their potential for side effects and misuse.

Lifestyle Changes

Certain lifestyle changes can also help people better manage the symptoms of narcolepsy. Some of the recommended changes include:

• Getting exercise each day
• Taking short naps during the day
• Sticking to a regular sleep schedule
• Avoiding smoking, caffeine, and alcohol
• Not eating large meals at bedtime
• Sticking to a relaxing nighttime routine

Coping

In addition to following the treatment advice of your doctor, there are also some things you can do that will help you cope with your condition. Some tips that may help:

Know Your Rights

The Americans With Disabilities Act requires employers to make reasonable accommodations for employees who have disabilities. See if you can structure your daily tasks so that you can do your work when you are at your most alert. If possible, see if your employer can change your schedule so that you can take short naps when you need to during the day. 

Schools, colleges, and universities should also take reasonable steps to accommodate your needs, such as setting a class schedule that will allow you to take naps.

Follow Safety Precautions

Certain activities can be dangerous if you have narcolepsy. This includes such things as driving or operating heavy machinery, but even many normally safe activities (such as walking downstairs or taking a shower) can be dangerous if you are experiencing sleep attacks or cataplexy. Some things you can do that may help:

• Take a short nap before you drive
• Only drive for short periods of time
• Find ways to stay alert while driving
• Look at alternative transportation options such as carpools or ride services

Seek Support

You may also find it helpful to enlist the support of your friends and family. Ask your loved ones for assistance with tasks such as driving or running errands. Joining a narcolepsy support group can also be a great way to find resources and support from people who are having similar experiences. 

Narcolepsy affects many different areas of your life and often makes it difficult to cope and function normally. If you are experiencing symptoms of stress or anxiety as a result of your condition, you may also find it helpful to talk to a therapist or other mental health professional.