Since the late 19th century, doctors have described a condition characterized by excessive daytime sleepiness, or sudden deep sleep attacks. This condition is known as narcolepsy. Other narcolepsy symptoms include:

• Cataplexy — A sudden episode of muscle weakness triggered by emotions, usually laughter
• Hypnagogic hallucinations — Vivid perceptions occurring during the transition between wakefulness and sleep
• Sleep paralysis — Moments of being unable to move when falling asleep or waking up, often continuing for a few seconds or minutes

It is very rare for a person with narcolepsy to have all four of the above symptoms.

Although there is currently no cure for narcolepsy, there are a number of treatment options available. Treatments for narcolepsy may include a variety of medications, such as amphetamine-like stimulants, antidepressants, and modafinil. Successful treatment for this condition also includes behavioral and lifestyle changes.

Etymology of Narcolepsy and Cataplexy

Etymology is the study of a word’s origin and how the meaning of that word has changed over time. The word “narcolepsy” was coined by a French physician named Jean-Baptiste-Edouard Gelineau in 1880. Its root lies in the French word “narcolepsie.” “Narcolepsie” comes from the Greek words “narke,” meaning “numbness or a stupor” (e.g., narcotic), and “lepsis” or “lepsy,” meaning “an attack or seizure” (e.g., epilepsy).

In 1902, L. Lowenfeld coined the term “cataplexy.” Cataplexy originates from the Greek word “kataplexis,” meaning “fixation of the eyes” or “stupefaction.” It was first used in a paper Lowenfeld published describing sudden sleep onset with episodes of muscle weakness triggered by emotions, usually laughter.

History of Narcolepsy

The first written account of a disorder fitting the description of a narcoleptic syndrome is from the 1600s. Thomas Willis, often known as “the founder of neuroanatomy,” described these symptoms in one of his patients. Jean-Baptiste-Edouard Gelineau (in 1880) and German physicians Karl Friedrich Otto Westphal (in 1877) and Franz Fischer (in 1878) documented the first official case reports of narcolepsy.

Most of these early descriptions of narcolepsy syndrome align with the symptoms that characterize narcolepsy as we know it today. Narcolepsy is said to usually — but not exclusively — present in children, adolescents, and young adults. Research suggests that more than half of people living with narcolepsy developed the condition before they turned 18 years old.

The Beginning of Sleep Research

In the early 20th century, the prevailing scientific understanding for narcolepsy with cataplexy was based in psychiatry and psychoanalysis. Even today, the Center for Narcolepsy at Stanford University’s School of Medicine is housed within the school’s Department of Psychiatry and Behavioral Sciences.

Researchers Eugene Aserinsky and Nathaniel Kleitman’s discovery of rapid eye movement (REM) sleep in 1953 introduced sleep medicine, somnology, and sleep research in its modern-day context. REM sleep is the deep, dream state of the standard person’s sleep cycle. It was not until this shift in sleep research that the concept of narcolepsy as a physiological condition was accepted. Gerald Vogel was the first to discover that disordered REM sleep played a role in giving rise to narcolepsy.

Although physicians in France and Germany first described narcolepsy in the late 19th century, much of the scientific research into the condition was conducted at Stanford University almost a century later. William Dement opened the first narcolepsy clinic at Stanford in 1964, though it closed the following year. Christian Guilleminault joined Stanford in 1970 to study sleep-disordered breathing, and the two researchers opened the Sleep Medicine Center that year.

Narcolepsy in the 1970s

In the mid-1970s, the multiple sleep latency test (MSLT), or daytime nap study, was used as diagnostic criteria for narcolepsy. The MSLT is a sleep study that tracks how fast a person falls asleep in a quiet setting during daytime hours. The MSLT is widely used to diagnose and differentiate between the different types of narcolepsy and idiopathic hypersomnia. Idiopathic hypersomnia is a related sleep disorder in which a person is excessively sleepy throughout the day, even with a good night’s rest. The word “idiopathic” means that the disease is of unknown cause.

Despite many earlier researchers’ assertions, it was not until around 1970 that doctors confirmed that narcolepsy and epilepsy were two different conditions. In 2014, the International Classification of Sleep Disorders listed narcolepsy (type 2) and narcolepsy with cataplexy (type 1) as separate disorders.

The Causes of Narcolepsy

Narcolepsy was originally believed to be a genetic disorder, or one that passes down through families. In 1973, scientists had a novel opportunity to study this theory with the discovery of the first narcoleptic dog. Several litters of puppies later, on July 29, 1976, scientists at Stanford genetically transmitted narcolepsy in dogs. Later they determined that genetic transmission of narcolepsy was inherited through a single autosomal recessive pattern, but only in some cases. “Autosomal recessive” means that two copies of the defective gene must be passed on to a child for the disease to develop. In other words, both parents must carry one copy of the abnormal gene, even if they do not have the disease themselves.

Narcolepsy in the 1990s

Technological advancements such as genetic typing, or genotyping, allowed scientists to narrow down the genes involved in narcolepsy in canine subjects. In 1998, Luis de Lecea and Takeshi Sakurai discovered hypocretin (or orexin). Hypocretin is the signaling molecule that controls our wakefulness. The neurons that make hypocretin are located in a part of the brain known as the hypothalamus. Soon after this discovery, the cases of narcolepsy in dogs were linked to hypocretin-2 gene deletions. Finally, in 2000, narcolepsy in human subjects was officially associated with very low levels or no levels of hypocretin.

The Current Focus of Narcolepsy Research

The National Center on Sleep Disorders Research and the National Institute of Neurological Disorders and Stroke sponsor and conduct critical research into narcolepsy. Some topics of current research include:

• The environmental and genetic factors that could lead to narcolepsy
• Animal models to better understand how hypocretin and other chemicals regulate sleep
• Therapeutic and treatment options with fewer negative side effects
• Abnormalities of the immune system in narcolepsy
• Autoimmune responses that destroy hypocretin neurons

Building a Community

MyNarcolepsyTeam is the social network for people with narcolepsy and their loved ones. On MyNarcolepsyTeam, more than 6,800 members come together to ask questions, give advice, and share their stories with others who understand life with narcolepsy.

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