A century ago, people worldwide experienced uncontrollable sleep due to a mysterious illness known as "sleepy sickness." Emerging in northern France in 1916, this disease, rather than fatigue, caused individuals to fall into deep, prolonged slumber.
The epidemic of the disease swept through India, Central America, North America, and Europe. The victims would frequently go into a deep sleep and wake up weeks or even months later. Regrettably, 30 to 40% of infected individuals died from drowsy illness, mostly from respiratory failure.
The outbreak had virtually completely subsided by 1930. But nobody is certain of the specific cause, how it spread, or whether the illness may recur today.
According to the National Institute of Neurological Disorders and Stroke, encephalitis lethargica is a rare disease with no known cause, but researchers suspect it may come from a virus. There was a pandemic of encephalitis lethargica (known then as "sleeping sickness") from around 1916 to 1930, but no recurrence of the epidemic has since been reported.
In some cases of encephalitis lethargica, people developed Parkinson's disease after recovery-sometimes as long as a year after the illness. Levodopa and other drugs to treat Parkinson's disease may be used to treat encephalitis lethargica, depending on the person's symptoms. The progression of the disease varies depending on complications or other disorders the person may have.
In a magazine article uncovered by Scientific American, Eleanore Carey, a young woman living in New York, described the disease as like "being buried in a pit as deep as the centre of the Earth.".
"After two months of illness, I was in little pain; in fact, I was very comfortable, provided they did not prod me, stand me on my head, turn me over in bed, or dash cold water on my face to wake me," she said.
"It was so heavenly just to be allowed to sleep, but these people around me seemed determined to prevent my being comfortable! When the idea finally crept through my sleeping brain that I must wake up, it seemed to be a physical impossibility. I wanted to be obliging, but I just could not."
