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Type 1 narcolepsy, also known as narcolepsy with cataplexy and narcolepsy-cataplexy, is a neurological disorder. In people with type 1 narcolepsy, the brain does not regulate sleep properly. People with narcolepsy experience parts of the sleep cycle randomly, at the wrong times, throughout the day.
Narcolepsy with cataplexy’s two defining symptoms are an overwhelming, often irresistible urge to sleep during the day known as excessive daytime sleepiness (EDS) and brief moments when a person’s muscles go completely slack (cataplexy). Cataplexy is the symptom that sets type 1 narcolepsy apart. Type 2 narcolepsy almost never includes cataplexy and is also known as narcolepsy without cataplexy.
Type 1 narcolepsy is easily confused with other disorders that cause EDS. Scientists believe estimates of the number of people with narcolepsy may be low, since many people who have narcolepsy haven’t been diagnosed and don’t know they have it. People experiencing symptoms of the disorder often mistake them for something else. Even doctors who are not sleep specialists may misdiagnose it.
Narcolepsy is considered a primary hypersomnia. Primary hypersomnia means the sleep disorder is a neurological disorder, not a symptom of another illness. Type 1 narcolepsy is a result of the destruction of brain cells (neurons) that produce hypocretin, a chemical necessary for regulating the cycle of sleep and wakefulness. As these neurons are destroyed, a deficiency of hypocretin (also called orexin) results. A low level of hypocretin is another difference between type 1 narcolepsy and type 2 narcolepsy. Like narcolepsy, other primary hypersomnias are usually linked to neurological or genetic conditions, such as Kleine-Levine syndrome — a rare disorder that also causes EDS.
Because EDS, one of type 1 narcolepsy’s main symptoms, often looks like falling asleep in meetings or at school, some people may view it as laziness. The symptoms of the disorder are often misunderstood and can draw stigma from others.3 Narcolepsy can have a debilitating impact on all aspects of a person’s life.
Although narcolepsy with cataplexy is a chronic condition that may or may not get worse with age, it is treatable and manageable. The negative effects the disorder has on the people who live with it are manageable too.
Type 1 narcolepsy is a disorder of the brain that straddles the medical line between mind and body. Narcolepsy has five main symptoms. Only 10 percent to 25 percent of people with type 1 narcolepsy experience all five.
Cataplexy looks different in different people. The muscle slackness can be as subtle as a droopy eye, or it can be more noticeable, like slumping over in their seat. Sometimes the muscles only stop working on one side of the body.
During a cataplectic episode, a person’s muscles suddenly go slack while they remain fully awake and aware, almost like they’re paralyzed. At times, not all the muscles are affected. A person may experience their jaw dropping, a knee buckling while walking, or a sudden weakness of the arms. These episodes can last a few seconds to a few minutes and are often brought on by surprise, laughter, or other emotional responses — usually positive emotions. In some people, fear and stress can also trigger cataplexy.
Type 1 narcolepsy is caused by a lack of a brain chemical called hypocretin. Without hypocretin, the body can’t properly control sleep functions. Hypocretin keeps the brain alert and body awake while preventing rapid eye movement (REM) sleep. Hypocretin is produced by neurons in a part of the brain called the hypothalamus. When enough of these neurons are damaged or destroyed, the body is unable to produce sufficient hypocretin. Type 1 narcolepsy symptoms are caused by hypocretin deficiency allowing the REM stage of the sleep cycle when it is not expected. Cataplexy is believed to be caused by the intrusion of REM sleep into wakefulness.
During REM sleep — the cycle where most dreaming happens — the body is paralyzed so you don’t act out your dreams, hurting yourself or others. For people living with type 1 narcolepsy, the body slips into this muscular paralysis mode suddenly, at the wrong time — like when a friend cracks a joke. This temporary lack of muscle function or paralysis is known as cataplexy or a cataplectic episode.
Hypocretin deficiency and developing narcolepsy with cataplexy are linked to several factors described below.
Researchers have identified several genes and gene mutations linked to type 1 narcolepsy and other sleep disorders. Genes control the groups of neurons that maintain brain and body activities during the four stages of sleep. Scientists also believe there is a genetic component to narcolepsy-cataplexy.
Scientists suspect the immune system and its responses to perceived threats may play a role in people developing narcolepsy. In a few instances, brain tumors or traumatic brain injuries have been the cause of narcolepsy-cataplexy. Researchers found a small group of people with narcolepsy-cataplexy that may have been a potential side effect of a 2009 vaccine against the H1N1 virus (bird flu) administered in certain countries. This vaccine is no longer used anywhere.
Autoimmune disorders cause the body's immune system to turn against itself, attacking its own healthy cells. Scientists have found instances of — and are doing further research into — the link between autoimmune disorders that cause brain changes and neurological disorders. One example is the research being done on Kleine-Levine syndrome, a rare neurological disorder, at Stanford Medicine’s Center for Narcolepsy, led by noteworthy sleep medicine specialist Dr. Emmanuel Mignot.
Read more about risk factors for narcolepsy.
Sleep happens in four stages. During each stage, the brain and neurons are undertaking a specific set of tasks which are linked to a certain set of brain waves and patterns. The average person experiences all four stages of sleep several times throughout the night.
The first stage of sleep is quite short, lasting a few minutes. The person’s heart rate and breathing slows down, and they begin to relax into a light sleep. Their brain waves also slow down compared to the patterns seen during times they’re awake.
In the second stage, the body relaxes even more. Breathing and heart rate slow down, and eye movement stops. Brain wave patterns continue to slow, but are interrupted by bursts of electrical activity.
The third stage occurs primarily during the first half of the night. Brain activity and all other markers reach their slowest of the night’s sleep. It may be a little difficult to wake someone up during the third stage.
REM sleep begins about an hour-and-a-half after a healthy person falls asleep. In people with narcolepsy, REM sets in much sooner. REM sleep is named for the quick movements a person’s eyes make behind closed lids. REM sleep is the stage where most dreaming happens. Brain scans show mixed wave patterns and activity. The muscles of the body paralyzed and breathing speeds up and gets more uneven. A person’s heart rate and blood pressure also rise, almost to the levels they’re at during waking hours.
With each sleep cycle, the REM stage gets longer. The longest cycles of REM happen during the wee hours, closer to dawn.
The amount of sleep a human needs each day changes as we grow. Babies can sleep as much as 17 out of 24 hours; adults need at least seven hours of sleep per 24 hours. When an adult isn’t getting enough sleep every day, less than seven out of 24 hours, it’s called short sleep duration. Several days or weeks of short sleep is known as sleep deprivation. Sleep deprivation can cause memory problems, moodiness, and poorer healing abilities when sick or injured, and can lead to EDS or hypersomnia.
Sleep is as vital to human development and our health as food and water. Sleep is important to helping nerve cells (neurons) function and work together to make the brain function. Our bodies also take the time that we are sleeping to clean out the toxins that build up in the brain throughout the day.
Between 135,000 to 200,000 people in the United States are diagnosed with narcolepsy. It affects men and women equally. Most people have type 1 narcolepsy, meaning that among people diagnosed with narcolepsy, about 80 percent experience cataplexy.
The symptoms of narcolepsy with cataplexy usually show up between ages 7 and 30, but can appear at any stage of life. Because the symptoms can be subtle or easily misunderstood, people often struggle for years with EDS, sleeplessness, and the devastating impact narcolepsy has on their lives. In fact, a study found that people experience their narcolepsy-cataplexy symptoms for an average of 14 years before getting a correct diagnosis.
Sleep is as important as nutrition for health. Health professionals are more and more aware that sleep plays an important role in a person’s overall health, life span, and manner of death. Narcolepsy, and sleep deprivation more generally, have been linked to type 2 diabetes, heart disease, obesity, and depression.
Children and younger people living with narcolepsy may struggle in school. They may have trouble staying awake and focused, and they may have other sleep disturbances like restlessness and poor concentration. They may also struggle in social situations and making friends. Among adults, the socioeconomic damages are the greatest. Poor job performance and the stigma associated with it create unfortunate professional outcomes.
Narcolepsy is the second most common cause of EDS, after sleep apnea — which affects nearly 12 million Americans. It can even create dangerous situations out of everyday tasks like driving to the grocery store. Over half of people diagnosed with narcolepsy reported falling asleep while driving. Type 1 narcolepsy is a lifelong disorder that can disrupt every aspect of a person’s life. However, it is manageable and its symptoms are treatable. Talk to your healthcare provider.
If a person suspects they may have narcolepsy, they should bring their concerns to a health care provider. They will likely be referred to a sleep medicine specialist, or a somnologist, as narcolepsy can be challenging to diagnose without a high level of training and expertise.
Narcolepsy is easy to diagnose if all five symptoms are present. But most people with type 1 narcolepsy do not experience all symptoms, and the symptoms are easily confused and misdiagnosed — both by the person experiencing them and by health providers. Symptoms of narcolepsy, especially cataplexy, look very different in young children and adults, adding to the difficulty around diagnosing and treating people with type 1 narcolepsy.
That's why a sleep medicine specialist is the best person to diagnose narcolepsy, with or without cataplexy. To do so, they use several tests and tools including:
Read more about how narcolepsy is diagnosed.
Type 1 narcolepsy is treatable and manageable. Treatments for narcolepsy usually include a combination of medications (stimulants and antidepressants) and behavioral or lifestyle changes. A person living with narcolepsy should work closely with their somnologist to find a treatment plan that fits their life and medical needs.
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Allen J. Blaivas, D.O. is certified by the American Board of Internal Medicine in Critical Care Medicine, Pulmonary Disease, and Sleep Medicine. Review provided by VeriMed Healthcare Network. Learn more about him here.
Nyaka Mwanza has worked with large global health nonprofits focused on improving health outcomes for women and children. Learn more about her here.
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