History of Narcolepsy
From LoveToKnow Sleep
Narcolepsy is an often-misunderstood sleep disorder, and this misunderstanding has shaped the history of narcolepsy for the past 300 years. In fact, several major advances in narcolepsy knowledge have only happened in the past 20 years.
Narcolepsy Defined
Narcolepsy is characterized by four main symptoms:
- Excessive Daytime Sleepiness (EDS), also called somnolence
- Cataplexy, episodes of sudden loss of muscle tone while a person is awake
- Sleep paralysis, an inability to move or speak while waking up or, less commonly, while falling asleep
- Hypnogogic hallucinations, or vivid dreams that occur while a person falls asleep
All narcoleptic patients have one or more of these symptoms, but only 20 to 25 percent of patients display all four symptoms, and some patients also have disturbed sleep at night.
Early History of Narcolepsy
While narcolepsy symptoms have probably been around since the beginning of time, the recorded history of narcolepsy begins in the 17th century with Oxford physician Thomas Willis. Interestingly, Willis also suggested caffeine as a treatment for narcolepsy, and stimulants have played a big part in the therapy of narcolepsy throughout history.
Theories of Narcolepsy
Willis' early descriptions of narcolepsy did not identify a cause for the disorder, and the early theories of what caused narcolepsy were unorthodox, at best. These early theories centered on the 19th century case of von Zastow, a convicted rapist whose excessive sleepiness attributed to excessive masturbation and repressed homosexuality.
Dr. Karl Friedrich Otto Westphal, a German doctor who was a full professor of psychiatry at the Berlin Charité Hospital at a time when the separation between neurology and psychiatry was virtually nonexistent, did not share this view. Dr. Westphal was the first to clinically describe narcolepsy as a physical disorder which often manifests along with cataplexy, episodes of sudden loss of muscle tone while a person is awake. The term cataplexy, coined in 1902 by a Dr.Loëwenfeld, comes from the Greek word kataplexis meaning “fixation of the eyes.”
Defining a New Disorder
In 1880, Dr. Jean-Baptiste-Edouard Gélineau coined the term narcolepsy, from the Greek words narke, meaning “stupor” or “numbness,” and lepsis, meaning “to seize.” Dr. Gélineau also connected the symptoms of excessive daytime sleepiness, cataplexy, and sleep paralysis as symptoms of one specific disorder. Using the term "narcolepsy" to mean all disorders that caused daytime sleepiness, this included illnesses that were not actually sleep disorders such as lethargic encephalitis. This confusion of terms was not resolved until 1907, when Dr. William Gowers sought in his book, The Border-Land of Epilepsy, to differentiate narcolepsy as a unique disorder separate from other conditions that could cause excessive daytime sleepiness.
Narcolepsy in the Twentieth Century
The latter half of the 20th century was an exciting time in the history of narcolepsy, and one major development occurred in 1957 when Mayo clinic doctors Robert Yoss and David Daly officially united the four classic narcolepsy symptoms. This new unity firmly established the “narcoleptic tetrad” as the definitive diagnostic criteria for narcolepsy.
Progress continued with Stanford University professor Dr. William Dement's establishment of the first narcolepsy clinic in San Francisco following an overwhelming local response to his recruitment efforts for a narcolepsy study.
Narcolepsy and Genetics
Dr. Dement went on to team with Dr. Merrill Mitler to examine genetic factors as a cause for narcolepsy, using dogs as the subjects for breeding experiments. The first litter of narcoleptic dogs was born in 1976, positively proving that narcolepsy could be passed down in families.
In the 1990s, researchers discovered specific information about the genetics of narcolepsy in the form of the HLA-DR2 allele. Human Leukeocytic Antigens (HLA) molecules are found on the surface of human white blood cells and help to coordinate the immune response. Genetic testing revealed that 90 percent of narcolepsy-cataplexy patients test positive for the presence of the HLA-DR2 allele, but because 20 percent of the general population also tests positive for the DR2 allele, HLA testing is not used to diagnose narcolepsy, but rather to identify a predisposition for the disorder.
The Importance of Hypocretin
The discovery of the role of hypocretin in narcolepsy is the most recent and one of the most significant discoveries in the study of the disorder. In 1998, researchers found that the lack of detectable levels of hypocretin in the cerebrospinal fluid causes the narcoleptic symptoms of excessive daytime sleepiness and cataplexy, making cerebrospinal fluid testing a standard part of the process of diagnosing narcolepsy.
Narcolepsy Today
The study of narcolepsy is continually evolving, with new therapies being tried and new discoveries about the origins of narcolepsy discovered. Narcolepsy researchers' commitment to forging new knowledge offers people with narcolepsy hope for a full and productive life in spite of their disorder.
Learn More
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