Narcolepsy is a complex, often misunderstood sleep disorder where people experience sudden, strong bouts of sleepiness during the daytime. These people struggle with lack of energy throughout the day and become intensely tired at unpredictable moments. They fall asleep for a few seconds to a few minutes at a time in any situation, be it sitting in class, cooking a meal, or taking a shower. Imagine staying up for two or three days without sleep. That’s the kind of exhaustion that people with Narcolepsy feel on a daily basis.
Most people with Narcolepsy also experience cataplexy, surprising episodes of full-body weakness brought on by strong emotions like fear or laughter. Normally during REM sleep, people’s bodies are temporarily paralyzed by the brain, but in cataplexy, this muscle weakness escapes the bounds of sleep and strikes in the middle of the day. People remain conscious while their limbs rapidly feel heavy and their knees buckle under them.
Narcolepsy usually begins in late adolescence, and excessive sleepiness is almost always the first major symptom. Because teenagers in general tend to need a lot of sleep, Narcolepsy can be easy to miss early on. Dozing off in class and napping a lot are usually viewed as typical in teenagers. However, as symptoms progress, they interfere with school, work, and social functioning, and the disorder goes far beyond the bounds of average adolescent behavior. Mood and behavior issues often appear from lack of good quality sleep in these adolescents as well. Cataplexy comes about a year or so after the initial sleepiness symptoms. These people also deal with many other sleep-related issues, including extremely vivid, stressful dreams, disruptive body movements during REM sleep, and generally poor quality sleep at night.
Causes and Risk Factors
Age and prevalence
Narcolepsy is a relatively rare condition and only affects about 1 in every 2,000 people. For most people, it begins during the adolescent years, but in a much smaller group, onset waits until the early 30s.
Autoimmune disease and cataplexy
People who experience cataplexy have low levels of the sleep hormone, orexin, because their immune systems attack the orexin producing cells in the brain. This autoimmune reaction is related to a heritable genetic trait. As a result, about 10% of people with Narcolepsy have a relative who also deals with the disorder. Simply having this gene is not enough, however; it only increases the risk. Seasonal infections like Strep throat or influenza (such as H1N1) are likely sources for triggering this autoimmune reaction, especially in children and adolescents, whose immune systems are more vulnerable.
Narcolepsy is called “secondary” when it appears after a brain injury that damages parts of the brain (like the hypothalamus) that manage sleep and alertness. These could be tumors, traumatic injuries, strokes, or infections in the brain. People in these situations also tend to have additional neurological problems and can experience excessive sleep as well.
The most common psychiatric issues that occur alongside Narcolepsy include Bipolar Disorder, depressive disorders, and anxiety disorders. One subtype of Narcolepsy that appears later than normal, between ages 30 and 40, shares a genetic link with deafness, dementia, and difficulties with coordination and balance. Another rare, genetic combination of disorders pairs Narcolepsy with obesity and type 2 diabetes. Weight gain frequently accompanies Narcolepsy, especially in children right after the disorder appears and before it is treated.
Making the diagnosis
The hallmark feature of Narcolepsy is sudden, repeated episodes during the daytime where people feel a powerful, unavoidable urge to sleep. These are often referred to as “sleep attacks”. They last at most a few minutes and can occur during normal, daily activities like eating, driving, or talking with others. Automatic behavior appears at these times as well. People continue to perform the activity they were just engaged in, but in a trance-like, unconscious state. These sleep attacks occur several times a week at least and last for multiple months.
These people can have measurable differences in the sleep hormone, orexin (also called hypocretin). Orexin is a chemical in the brain that helps to regulate sleep and wakefulness, among other functions. People with Narcolepsy can have orexin levels at or below a third of average.
Many people with Narcolepsy experience a phenomenon known as cataplexy, which usually follows a strong emotion, such as laughter or anger. These are sudden episodes of full-body muscle weakness lasting from a few seconds to a few minutes. People are at risk of falls and cannot protect themselves during these events, yet they remain conscious and aware of their surroundings. Cataplexy can also appear as involuntary, odd facial and mouth movements in children and people with recently-diagnosed Narcolepsy.
Severity is based on how often these events happen. Cataplexy occurs less than once a week and daytime sleepiness is minor in mild cases. However, in the worst times, cataplexy happens many times a day, and people struggle with a near-constant, powerful need to sleep.
Sleep studies reveal that people with Narcolepsy fall asleep much faster than most people. They go into REM sleep more quickly after falling asleep as well, and disturbing nightmares and dreams are common. These people sometimes experience vivid, dream-like hallucinations as they are falling asleep and as they are waking up. Sleep paralysis also occurs during these times, where people are partially awake but cannot move or talk for a short time. Other issues surrounding sleep are also common, including teeth grinding, sleep walking, sleep eating, and urination during sleep.
Before performing any formal sleep tests, doctors will have people keep a diary for a couple weeks recording symptoms they have during the night and day. Following this, an overnight sleep study (polysomnogram) to look for quick-onset REM sleep and to rule out other potential causes of daytime sleepiness. On the day after a sleep study, people also have a Multiple Sleep Latency Test (MSLT) to assess daytime drowsiness by measuring how long they take to fall asleep in several naps. As at night, quickly falling into REM sleep during daytime naps indicates the presence of Narcolepsy.
Medications that help people stay awake during the day are the most common first choice option for treatment. The main option is Provigil (modafinil), a medication that keeps people alert without the addictive potential of other stimulants. However, if Provigil is not effective, stimulants like Ritalin (methylphenidate) and Adderall (amphetamine) are second line options that can be used, although only with careful monitoring for abuse.
The notorious medication gamma-hydroxybutyrate (GHB) is sold as Xyrem (sodium oxybate) and offers a single treatment that manages both daytime sleepiness and cataplexy in people with Narcolepsy. Xyrem is taken twice nightly, once just before bed and then again, a few hours later in the middle of the night. This medication is a high risk for abuse, and prescriptions are closely monitored by the F.D.A. Because it is so strongly sedating, people need to be careful not to mix it with alcohol and must wait for its effects to wear off in the morning before driving.
Some antidepressants help manage cataplexy and additional disruptive sleep symptoms (though they do not reduce daytime sleepiness). They can reduce the excessive REM sleep that people with Narcolepsy have and can normalize their sleep cycles to create more restful sleep. These medications include Prozac (fluoxetine), Effexor (venlafaxine), and Anafranil (clomipramine).
Even with the help of medications, most people with Narcolepsy will still need to use a few lifestyle techniques to help manage their symptoms. Many people choose to schedule a few short naps throughout each day to keep their sleepiness in check. Getting good sleep at night is key, too, and this requires going to bed and getting up at roughly the same times from day to day. Exercise a few hours before bed can also help people get to sleep. Alcohol, caffeine, and nicotine all disrupt sleep at night as well and should be avoided. Big meals right before bed can also make falling asleep harder.
Avoiding daytime drowsiness
Many medications, both prescription and over the counter, can make people tired and will provoke the daytime sleepiness that is so characteristic of Narcolepsy. These include allergy medications like Benadryl (diphenhydramine) and cold medications like Robitussin (dextromethorphan), which people with Narcolepsy should avoid if possible.
Driving and other risky activities
Dealing with daytime sleepiness is a major hurdle to staying safe while driving. Dozing off behind the wheel for even a second or two can put lives in danger. While individual states have different laws and procedures on the subject, a diagnosis of Narcolepsy does not automatically bar anyone from driving. In general, decisions about driving are best made with the help of the doctor treating the Narcolepsy. They will help determine how well the symptoms are controlled and will work with people to create a set of safety guidelines for driving. These may include limiting driving alone, taking turns driving on long trips, breaking up drives with scheduled naps at rest stations, and avoiding driving at night if possible.
Numerous other activities that might seem harmless suddenly become dangerous if someone suddenly falls asleep. Bathing, swimming, cooking, or simply crossing a busy street all present very real risks for people with Narcolepsy. The key to staying safe is good self-monitoring: keeping track of sleepiness and knowing personal triggers for cataplexy.
Work and school performance
People with Narcolepsy are protected under the Americans with Disabilities Act (ADA), which compels companies to work with their employees with particular medical needs. Allowing for a few naps over the course of the workday is one of the most important arrangements employers can make for people with Narcolepsy. People who are in school will need to develop a similar plan for napping between classes.