Narcolepsy
Narcolepsy is a chronic brain condition that disrupts the ability to control when you sleep and wake. People with this disorder often experience overwhelming sleepiness during the day and may fall asleep suddenly, along with other symptoms that can significantly affect daily life. While narcolepsy presents serious challenges, it responds well to treatment, allowing many people to manage the condition effectively.
Table of contents
- What is narcolepsy
- Main symptoms of narcolepsy
- Two types of narcolepsy
- What causes narcolepsy
- Who is affected by narcolepsy
- How narcolepsy is diagnosed
- Treatment options
- Living with narcolepsy
- Driving considerations
What is narcolepsy
Narcolepsy is a sleep disorder that makes it extremely difficult for the brain to regulate sleeping and waking patterns normally[1]. This neurological disorder (a condition affecting the nervous system) affects how your brain controls sleep-wake cycles, causing people to feel very sleepy throughout much of the day even after getting adequate rest at night[2].
In a typical sleep cycle, people enter rapid eye movement sleep (REM sleep, the stage when most dreaming occurs) after about 60 to 90 minutes. The brain keeps muscles limp during this stage to prevent acting out dreams. However, in people with narcolepsy, the regulation of sleep and waking is disrupted, causing what doctors call fragmented sleep[2]. This means the boundaries between being awake and asleep become less distinct, and elements of sleep can intrude into wakefulness[2].
People with narcolepsy frequently enter REM sleep much more quickly than others, often within 15 minutes of falling asleep[2]. They can also experience muscle weakness or dream activity typical of REM sleep while they are fully awake[2].
Main symptoms of narcolepsy
There are four main symptoms associated with narcolepsy, though most people with this condition don’t experience all four[1]. The symptoms can vary significantly among individuals, and while they may improve over time, they never completely go away[2].
Excessive daytime sleepiness is the primary symptom and affects everyone with narcolepsy[1]. This causes severe daytime sleepiness that doesn’t improve even after getting enough sleep at night[2]. People with narcolepsy and experts often describe these episodes as “sleep attacks,” where an overwhelming feeling of sleepiness comes on quickly[2]. Sleep can happen anywhere and at any time, even during activities like working, talking with friends, eating, or driving[3]. Between sleep attacks, individuals can have normal levels of alertness, particularly when doing activities that keep their attention[2].
Cataplexy involves sudden episodes of muscle weakness, often triggered by strong emotions such as laughter, fear, anger, stress, or excitement[2]. Under normal circumstances, your brain shuts down most muscle control when you sleep to keep you from acting out dreams. People with cataplexy experience similar sudden muscle weakness while awake[1]. Mild cataplexy may only affect your face and neck, such as your jaw dropping involuntarily, or just one side of your body. Severe cataplexy can make you collapse to the ground, which can lead to injuries[1]. These events usually last a few minutes or less, but you may not be able to move or talk during that time[1]. Cataplexy may appear weeks or even years after excessive daytime sleepiness begins[2].
Sleep paralysis is a temporary inability to move or speak when waking up or falling asleep[1]. Your brain normally shuts down muscle control to keep you from acting out dreams, but this should end when you wake up. However, if you have sleep paralysis, your body doesn’t regain muscle control as it should. You can still breathe and move your eyes, but you can’t talk or move the rest of your body[1]. These episodes are usually very short-lived, lasting only a couple of minutes at most[1].
Sleep-related hallucinations happen right after falling asleep or right before or during waking[1]. These dreams often come as you fall asleep (called hypnogogic hallucinations) or just before or during waking (called hypnopompic hallucinations)[4]. Hallucinations during sleep paralysis are very common and often vivid and extraordinarily frightening[1].
Additional symptoms can include excessive dreaming and waking during the night[4]. Many people with narcolepsy also experience fragmented sleep at night, meaning they can’t stay asleep for long periods of time[2].
Two types of narcolepsy
Narcolepsy is divided into two types based on whether cataplexy is present[3].
Narcolepsy type 1 (formerly called narcolepsy with cataplexy) involves cataplexy. About 20% of narcolepsy cases are type 1[1]. Most people with type 1 narcolepsy have cataplexy[3]. This type occurs when nearly all of the neurons that contain hypocretin (also called orexin, a brain chemical that regulates wakefulness) are lost[6]. People with type 1 narcolepsy have very low levels of hypocretin[7].
Narcolepsy type 2 (formerly called narcolepsy without cataplexy) doesn’t involve cataplexy. The majority of narcolepsy cases, about 80%, are type 2[1]. Most people with type 2 narcolepsy don’t have cataplexy[3]. The cause of narcolepsy type 2 is not entirely clear[6].
What causes narcolepsy
Narcolepsy is often caused by a lack of the brain chemical hypocretin, which regulates wakefulness[4]. The lack of hypocretin is thought to be caused by the immune system mistakenly attacking the cells that produce it or the receptors that allow it to work[4]. This suggests narcolepsy may be an autoimmune process (when the body’s defense system attacks its own healthy cells), possibly triggered by an infection[6].
A specific genetic marker called HLA haplotype DQB1*06:02 is present in 95% of narcolepsy type 1 patients, though this marker is also present in about 20% of the general population without narcolepsy[6]. This means having this genetic marker doesn’t guarantee someone will develop narcolepsy, but it does appear to increase susceptibility.
Several factors have been suggested as possible triggers of narcolepsy, including hormonal changes during puberty or menopause, major psychological stress, and certain infections[4]. In 2009, there was an increase in reported narcolepsy type 1 cases in Europe after receiving a specific influenza vaccine, and there was also an increase in reported cases in non-vaccinated patients after wild influenza infection[6].
Less commonly, trauma and tumors may result in narcolepsy[6]. However, the exact cause of narcolepsy is often unclear, and not all cases can be fully explained[4].
Who is affected by narcolepsy
It’s difficult to know exactly how many people have narcolepsy because many cases are thought to go unreported[4]. The condition is estimated to affect about 30,000 people in the UK[4] and approximately 200,000 people in the United States[7].
Men and women are thought to be affected equally by narcolepsy, although some studies have suggested the condition may be more common in men[4].
The symptoms of narcolepsy often begin during adolescence[4]. Close to 50% of patients develop symptoms in their teenage years[6]. However, narcolepsy is usually diagnosed between the ages of 20 and 40[4]. The condition is often under-diagnosed, and delays of 5 to 10 years are common before making a firm diagnosis[6].
Once narcolepsy develops, the person will have it for the rest of their life[2]. It is a lifelong condition and does not have a cure[3].
How narcolepsy is diagnosed
A healthcare professional may suspect narcolepsy based on your symptoms of daytime sleepiness and sudden loss of muscle tone[9]. Your doctor will likely ask about your sleeping habits and any other symptoms you have[4]. They may also carry out tests to help rule out other conditions that could be causing excessive daytime sleepiness, such as sleep apnea, restless legs, or an underactive thyroid gland[4].
You’ll likely be asked to fill out the Epworth Sleepiness Scale, which uses short questions to measure your degree of sleepiness[9]. You may also be asked to write down your sleep pattern for a week or two, and you might wear a device on your wrist called an actigraph that measures periods of activity and rest[9].
If necessary, you’ll be referred to a specialist in sleep disorders who will analyze your sleep patterns[4]. Formal diagnosis usually requires staying overnight at a sleep center for in-depth sleep analysis[9].
A polysomnography (sleep study) measures signals during sleep using electrodes placed on your scalp. This test measures your brain waves, heart rate, breathing, and records your leg and eye movements[9]. For this test, you spend the night at a sleep lab where technicians connect you to devices that measure your breathing, brain and muscle activity, and eye movements[7].
A Multiple Sleep Latency Test measures how long it takes you to fall asleep during the day[9]. This is also known as a “nap test” because it measures daytime sleepiness and ability to fall asleep[7]. You’ll be asked to take four or five naps at a sleep center, each two hours apart. Specialists observe your sleep patterns. People who have narcolepsy fall asleep easily and enter into REM sleep quickly[9]. The test can help determine how quickly you enter REM sleep, with people with narcolepsy entering this stage much faster than others[7].
In some cases, genetic tests and a lumbar puncture may be performed[9]. Sometimes cerebral-spinal fluid is tested for the presence or lack of orexin[15].
Treatment options
There’s currently no cure for narcolepsy, but making changes to improve your sleeping habits and taking medicine can help minimize the impact the condition has on daily life[4]. Treatment of narcolepsy has both non-medication and medication components[14].
Lifestyle changes and healthy sleep habits
Most patients improve if they maintain a regular sleep schedule, usually 7.5 to 8 hours of sleep per night[14]. Keeping to a strict bedtime routine can help, so you should go to bed at the same time each night whenever possible[4].
Taking frequent, brief naps evenly spaced throughout the day is one of the best ways to manage excessive daytime drowsiness[4]. Scheduled naps during the day may help, with many people benefiting from 15 to 20 minute naps[14]. This may be difficult when you’re at work or school, but a doctor or specialist may be able to devise a sleep schedule that will help you get into a routine of taking naps[4].
Other helpful habits include relaxing before going to bed, ensuring you have a good sleeping environment (keeping your bedroom at a comfortable temperature, quiet, and free from distractions), avoiding caffeine and alcohol before going to bed, not exercising too close to bedtime (leave at least 2 hours between finishing exercise and going to bed), and not eating large, heavy meals before going to bed[11].
Regular exercise can be beneficial, with at least 20 minutes of exercise a day helping you sleep better at night[18]. Daily exercise should be done at least five hours before bedtime so you have time to wind down, and exercising during daylight hours also helps regulate your circadian rhythm[18].
Medications
If your symptoms are particularly troublesome, you may be prescribed medicine that can help reduce daytime sleepiness, prevent cataplexy attacks, and improve your sleep at night[4]. These medicines are usually taken as daily tablets, capsules, or drinkable solutions[4].
Stimulants help keep you awake during the day by stimulating your central nervous system[14]. Common stimulants include modafinil, which is often used as the first treatment and has a lower risk of addiction and fewer side effects than most other stimulants[13]. Modafinil is a wake-promoting agent that doesn’t appear to affect total sleep time or suppress REM sleep, with headache being the most common side effect[14]. Other stimulants include methylphenidate, which is frequently used for narcolepsy treatment[14], and newer options like pitolisant and solriamfetol[11].
Antidepressants, specifically tricyclics and SSRIs, may be used to help treat cataplexy in patients with type 1 narcolepsy[13].
Sodium oxybate is a medicine that can improve sudden loss of muscle control and help you sleep at night, which can also reduce daytime sleepiness[11]. Sodium oxybate is a liquid medicine you drink at night in two doses: the first when you get into bed, and the second 2.5 to 4 hours later[11]. You may need to use an alarm clock to ensure you take the medicine at the right times[11].
Common side effects of stimulants can include headaches, nausea, nervousness, difficulty sleeping at night, stomach ache, irritability, and weight loss[11]. It’s important to speak to your doctor if you have persistent or troublesome side effects, as they may be able to prescribe an alternative medicine[11].
Living with narcolepsy
As well as being a difficult condition to live with, narcolepsy can be difficult for others to understand[11]. Some of the symptoms, such as sudden loss of muscle control, can be frightening for people who are unaware of the condition[11].
If narcolepsy is not diagnosed or treated, it can interfere with emotional well-being, social interactions, and the ability to think clearly, which can affect school, work, and social life[2]. In an attempt to avoid attacks, some people may become emotionally withdrawn and socially isolated[4].
You may find it useful to talk to your friends and family about your condition[11]. Speaking openly with family, friends, and co-workers about your condition can relieve some stress[18]. Because many people don’t understand narcolepsy or its effects, talking about it can help build a strong support team[18].
If you have children with narcolepsy, tell their teachers about the condition. It’s important that teachers are aware so they don’t mistake their behavior for laziness or staying up too late at night[11]. Children should be encouraged to participate in after-school activities and sports, as a well-designed exercise program can be beneficial and stimulating[14].
You might also find it useful to contact a local or national narcolepsy support group, such as Narcolepsy UK[11]. They’ll be able to provide advice about living with narcolepsy and can put you in touch with other people in a similar situation[11].
With care and precautions, it’s possible to manage this condition and adapt to its effects[1]. With proper treatment, medications, and lifestyle changes, many people with narcolepsy can manage their symptoms and live full, productive lives[15].
Driving considerations
If you’re diagnosed with narcolepsy, it may affect your ability to drive[4]. It can be especially dangerous to fall asleep while driving[3].
If you have a history of sleepiness while driving, you should not drive until you have that addressed and improved with your sleep doctor[19]. People with narcolepsy have a higher tendency to get in car accidents, partly due to lapses in reaction time that can happen when you feel sleepy[19].
You should stop driving immediately and inform the relevant licensing authority when diagnosed. You’ll need to complete a medical questionnaire so your individual circumstances can be assessed[4]. You’ll usually be allowed to drive again if your narcolepsy is well controlled and you have regular reviews to assess your condition[4].
Once you get your narcolepsy symptoms under control with treatment, you can take extra steps to drive safely. If you think there’s a chance you might get sleepy during a shorter drive, take a 15 to 20 minute nap before you hit the road to feel more alert[19].
