1,000,000 people across the globe suddenly became prisoners in their own bodies. But the part about how it ended is even stranger

Starting in 1915, a strange disease began spreading around the world that would terrify millions of people.

The illness was called encephalitis lethargica, but most people knew it as sleeping sickness. At first, victims would get what seemed like a regular cold or flu. They would feel tired and sick, with a sore throat and headache. But then something much worse would happen. They would start falling into a deep sleep that they could not wake up from properly.

The disease moved quickly from country to country during the First World War. Soldiers traveling between nations probably helped it spread faster. As per Wikipedia, a doctor in Vienna named Constantin von Economo was one of the first to study it carefully in 1917. Doctors think that over a million people got sick from it. Around half a million people died, but many others ended up in an even worse situation. They survived, but they were stuck in a kind of living nightmare.

The truly scary part was what happened to the people who lived through the first stage of the illness. They could not move or talk, even though their minds were still working. Von Economo wrote about how these patients would fall asleep for very long periods, but if someone woke them up, they seemed to understand everything going on around them. Then they would fall right back asleep. Some people stayed like this for ten, twenty, or even forty years. They were basically frozen like statues.

The mystery deepens when you look at how it vanished

Then something really odd happened. The disease just stopped. By 1927, hardly anyone was getting sick with it anymore. By the 1930s, it was completely gone. Doctors wrote thousands of papers trying to figure out what caused it, but nobody could find the answer. 

Some thought it might be connected to the big flu outbreak in 1918, but that did not quite add up. Today, scientists think it might have been caused by the body attacking itself after fighting off an infection, but they still are not sure. Like other strange medical phenomena that baffled scientists, nobody knows why it started or why it stopped.

I didn't know that the 1918 Spanish Flu virus was different from the 1917 Spanish Flu virus, did you?@realDonaldTrump knew.
So did Jeffrey Taubenberger.
So did Dr. Fauci.

1917 was bird flu, just like H7N9,
and it caused
Encephalitis Lethargica – Sleeping Sickness.

COVID was… pic.twitter.com/45lV6Y9sh9

— John Cullen (@I_Am_JohnCullen) August 18, 2025

Many years later, in 1969, a doctor named Oliver Sacks found some of these frozen patients still alive in a hospital in New York. They had been sitting in chairs or lying in beds, unable to move, for almost fifty years. 

Sacks tried giving them a new medicine called L-DOPA that was being used for Parkinson’s disease. What happened next was almost unbelievable. The patients suddenly came back to life. They could walk, talk, and act like normal people again after decades of being trapped inside their bodies.

Awakenings movie is based on true story of neurologist Oliver Sacks' work with patients suffering from encephalitis lethargica, a mysterious sleeping sickness epidemic caused catatonia. Sacks, portrayed as Dr. Malcolm Sayer (Robin Williams) used the drug L-DOPA to awaken patients pic.twitter.com/Hr8NIjd9H2

— A L I (@LEEFREESPEECH) September 10, 2025

But the miracle did not last. After some time, the medicine stopped working. The patients went back to being frozen, just like before. Some of them even got worse. Sacks wrote a book about his work with these patients called Awakenings, and it later became a movie. 

The story of these patients and their decades-long struggle was nearly lost to history until Sacks shared what he learned. Today, the disease almost never shows up anymore, but doctors still worry it could come back someday. The whole thing remains one of the biggest unsolved mysteries in medical history.