What Is Narcolepsy?

Narcolepsy is a sleep disorder characterized by excessive sleepiness during the day. It can lead to profoundly disabling symptoms, ranging from unexpected bouts of sleep to emotionally triggered muscle weakness that may lead to a person collapsing on the floor (cataplexy).

Narcolepsy is not simply being overtired. Those who have it are unable to stay awake for periods of time no matter the situation.

Types of Narcolepsy

There are two main types of narcolepsy—type 1 and type 2. They are differentiated based on two factors:

• The presence or absence of cataplexy
• The measurement of a brain hormone called hypocretin (orexin), which helps keep you alert and awake.

Narcolepsy Symptoms

The symptoms of narcolepsy usually begin in a person's teens or early twenties, but may first occur in childhood or even late adulthood, though this is rare.

There are four main symptoms of narcolepsy. Only one in three people with narcolepsy has all four.

Daytime Sleepiness

Every person with narcolepsy experiences excessive daytime sleepiness, where they doze off at random times during the day when they should be awake. Sometimes this occurs without much warning, which can, unfortunately, lead to injury.

It's important to note that people with narcolepsy do not sleep more than healthy individuals. Their sleep-wake patterns are simply disrupted, and they enter into REM (rapid eye movement) sleep more rapidly than normal.

Cataplexy

Cataplexy occurs when a person experiences a sudden, short-lived loss of voluntary muscle tone (weakness) while awake. This weakness is emotionally-triggered, meaning its onset occurs when a person is feeling a strong emotion, like amusement, anger, or surprise.

The weakness of cataplexy usually begins in the face and then moves to the knees. It may result in jaw-dropping, head nodding, knees sagging, limping, and in severe cases, falling. The good news is that the weakness is transient, with episodes usually lasting from a few seconds to a few minutes.

Hallucinations

People with narcolepsy may experience intense, vivid hallucinations while awake but transitioning to sleep called hypnagogic hallucinations. As a result, a person may see, hear, or feel things that are not really there.

These occur as a result of the brain generating dreams while awake.

Sleep Paralysis

Sleep paralysis means that a person cannot move or speak for one to two minutes right after waking up. This may also happen just prior to falling asleep. Sometimes the paralysis is accompanied by hallucinations or a feeling of suffocation, which can be extremely frightening.

Other

In addition to the above symptoms, many people with narcolepsy suffer from psychiatric concerns, most notably depression and/or anxiety.

Obesity is also common in narcolepsy and is believed to be related to loss of hypocretin.

Causes

Narcolepsy was first described by the French physician Jean Gelineau in 1880, and it is one of the least understood sleep disorders.

Narcolepsy appears to occur because of hypocretin deficiency. Hypocretin is thought to promote wakefulness and maintain normal muscle tone, so it makes sense that its loss would lead to sleepiness and the sudden weakness seen in cataplexy.

It is thought that the immune system, which typically is responsible for fighting infection, may target and destroy hypocretin-containing neurons (nerve cells). Why a person's immune system turns against these neurons in the brain remains unclear. Many experts suspect that an infection (typically a cold or flu) may trigger the body to react against itself in genetically-susceptible individuals.

Interestingly, certain vaccines may play a role in the development of narcolepsy as well. In fact, an increased risk of narcolepsy was found following vaccination with Pandemrix, a monovalent H1N1 influenza vaccine produced for the 2009 to 2010 flu season and only used in Europe. Use of this vaccine has since been halted.

Besides autoimmunity, narcolepsy may also be caused by rare lesions within the brain that result because of tumors, strokes, or other inflammatory insults.

Finally, there is likely a genetic component to narcolepsy, as this disorder is found among family members. Up to 10% of individuals diagnosed with narcolepsy with cataplexy report having a close relative with the condition.

Diagnosis

If you believe you may be suffering from narcolepsy, your healthcare provider—usually a sleep specialist—will first perform a medical history and physical exam. Then, various sleep tests may be recommended to clinch the diagnosis of narcolepsy or evaluate for other sleep disorders.

Medical History

During your appointment, the healthcare provider will start by asking you several questions about your sleep. For example:

• Do you feel rested in the morning, but then sleepy for the majority of the day?
• Do you find yourself falling asleep at inappropriate times?
• When you laugh or become angry, do you ever experience sudden muscle weakness?
• When you wake up, are you ever not able to move or speak?

Answering "yes" to one or more these questions usually warrants further investigation into a possible diagnosis of narcolepsy.

Of course, in order to consider other causes behind your symptoms, your healthcare provider will also ask questions like:

• Are you taking any medications to help you sleep or that make you tired? (A medication may be the culprit behind your daytime sleepiness.)
• Do you experience morning headaches and/or does your partner say you snore loudly? (These could be clues of an alternative diagnosis, like sleep apnea.)

Physical Exam

In addition to a medical history, your healthcare provider will perform a physical exam, which will include a neurological exam, mostly to rule out other causes for daytime sleepiness or muscle weakness.

Sleep Tests

If your healthcare provider is suspicious of a diagnosis of narcolepsy based on your history and exam, you will need to undergo further testing. Typically, your healthcare provider will have you complete a sleep log or actigraphy in order to record how much sleep you are getting.

This will then be followed by an overnight sleep study called a polysomnogram (which is often normal in people with narcolepsy), followed by a study the next day called a multiple sleep latency test (MSLT), which is a daytime nap test.

A diagnosis of narcolepsy is strongly supported if, on the MSLT, you fall asleep in less than eight minutes on average across all naps and enter REM sleep during two or more naps.

Lumbar Puncture

While not routinely done, if your MSLT is hard to interpret or your case is otherwise ambiguous, a lumbar puncture (spinal tap) may be performed. During this test, a sample of cerebrospinal fluid is obtained in order to measure the concentration of the hormone hypocretin.

A hypocretin level that is less than or equal to 110pg/mL (picograms per milliliter) is consistent with a diagnosis of type 1 narcolepsy. A normal of hypocretin supports a diagnosis of type 2 narcolepsy.

Treatment

Narcolepsy is a chronic condition with no cure, as the destruction of hypocretin-containing cells is typically complete and the resulting deficit is permanent. Therefore, narcolepsy requires persistent treatment.

The good news is that behavior modifications, as well as different medications, can be used to treat the symptoms associated with narcolepsy.

Behavioral Modifications

Examples of behavior changes that can decrease the symptoms of narcolepsy include:

• Avoiding medications or substances that induce drowsiness or sleepiness (e.g., allergy medicines or alcohol)
• Moderating caffeine intake, as excessive caffeine intake can worsen insomnia, which can worsen daytime sleepiness
• Maintaining a regular, sufficient sleep schedule (sleep deprivation can worsen narcolepsy symptoms)
• Scheduling one to two naps during the day

It's also important for a person with narcolepsy to follow up with their primary care physician or other healthcare provider as directed. Weight problems and side effects from medications can be addressed and monitored.

Sometimes a referral to a mental healthcare professional is warranted not only to address possible psychiatric conditions, but to aid in coping with the daily life challenges of living with narcolepsy.

REM-Suppressing Medications

Cataplexy, sleep paralysis, and hypnagogic hallucinations occur during REM sleep, which can be strongly inhibited by the brain chemicals, norepinephrine and serotonin. Therefore, medications, like Effexor (venlafaxine) and Prozac (fluoxetine), which increase the brain levels of norepinephrine and serotonin, can help reduce these symptoms of narcolepsy.

Stimulant Medications

Daytime sleepiness in narcolepsy can be treated with stimulant medications, such as:

• Provigil (modafinil)
• Nuvigil (armodafinil)
• Ritalin (methylphenidate)

Sodium Oxybate

Xywav (sodium oxybate) is another medication used to reduce cataplexy, usually more severe cases. It can also be used to treat daytime sleepiness.

On the Horizon

It's good to remain hopeful about the future treatment of narcolepsy. New therapeutics may be able to prevent, slow, or reverse the destruction of the hypocretin-containing cells in susceptible individuals. Regeneration of this population of brain cells with stem cell transplants may also eventually be possible.

Though these interventions are still distant, there remains the possibility that one day, narcolepsy may ultimately go away in those who are afflicted with it.

Coping

No doubt, the debilitating symptoms of narcolepsy pose challenges to daily life. People with narcolepsy may struggle to keep up with work or school, and they may find it difficult to maintain social and romantic relationships.

While medication and behavior changes can help a person manage their disease well, narcolepsy education amongst a person's loved ones and peers is an essential coping tool.

If you have narcolepsy, please consider telling others about your condition (or invite them to read about it through reliable online resources). By educating people, you are giving them the opportunity and foresight to provide you with the support you need, both emotionally and physically.

Finally, since mood disorders are common in narcolepsy, if you are experiencing symptoms of depression (for example, feeling sad all the time or losing interest in activities you once enjoyed) or symptoms of anxiety (for example, worrying all the time or enduring panic attacks), please be sure to reach out to your healthcare provider. You may benefit from talk therapy and/or taking an antidepressant or anti-anxiety medication.