Many cases of mass hysteria are triggered by extreme, sudden stress, and strange or mysterious odors.

Mass hysteria (or mass sociogenic illness) begins when individuals under stress unconsciously convert that tension into physical illness. Peers, family members or friends may also begin exhibiting the symptoms through contagion, in which the suggestion of a threat can be enough to create symptoms.

In December of 1997, some 12,000 Japanese schoolchildren experienced illnesses ranging from nausea to seizures while watching an episode of the cartoon Pokémon.

At the time, the incident was attributed to photosensitive epilepsy, in which bright flashing lights are the triggers for symptoms, but the bizarre episode retained many of the hallmarks of mass hysteria.

Pokémon is a cultural phenomenon that is ubiquitous, having spawned countless video games, comics, websites, videotapes, magazines, clubs, music CDs, books, trading cards, three films, and, of course, an animated television series.

The episode in question (number 38 Dennou Senshi Porigon) aired on December 16, 1997. In the middle of the episode, flashing lights filled the screen and about 30 minutes later, more than 600 children were taken to hospitals complaining of various symptoms. When the incident was covered on the news that evening and the flashing incident was replayed, a second wave of children fell ill and had to seek medical attention.

Information regarding exactly how many children became sick (and when) and how many were taken to hospitals is difficult to determine, and at times contradictory, but specific figures are known for certain areas.

“Children went into a trance-like state, similar to hypnosis, complaining of shortness of breath, nausea, and bad vision … Victims’ families reported that children passed out during the broadcast, went into convulsions, and vomited,” stated the Yomiuri Shimbun newspaper.

“Toward the end of the program, there was an explosion, and I had to close my eyes because of an enormous yellow light like a camera flash,” said one of the children affected, Takuya Sato, 10.

Many aspects of the Pokémon panic support the diagnosis of mass hysteria. The Pokémon-induced symptoms such as convulsions, fainting and nausea are commonly associated with that syndrome. Despite this, the fact that most of the children were separated in their own homes and were thus unable to be influenced by the other children places the entire diagnosis in doubt.

Although the bright flashes were believed to be at fault, they had been used hundreds of times before without incident. The technique, called paka-paka, uses different-colored lights flashing alternately to create tension. It is a common technique used in anime, and many other popular cartoons.

Epilepsy experts were skeptical that an epilepsy-like syndrome triggered the seizures experienced by hundreds of viewers.

The number of kids reported to have been affected the next day shot up a staggering 12,000 cases. This number was cited only after extensive media coverage and the opportunity for contagion in the schools occurred. The children had “at least minor symptoms,” with 685 taken to hospitals, according to one newspaper.

The mystery was finally solved in 2001, when it was discovered that the symptoms found in most children were caused by mass hysteria, triggered by the initial wave of epileptic seizures.

Go figure. And watch out for those flashing lights!




M Dee Dubroff is the penname of this freelance writer and former teacher originally from Brooklyn, New York. A writer of ghostly and horror fiction, she has branched out into the world of humorous non fiction writing and maintains eight web sites covering a wide variety of topics. She also writes feature articles for several local newspapers. Her book entitled: A Taste of Funny, and her website, Eat, Drink And Really Be Merry ( feature many well researched and humorous articles on the subject of food and drink.