Pokemon Contagion: Photosensitive Epilepsy or Mass Psychogenic Illness?

South Med J. 2001;94(2) 

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On December 17, 1997, TV Tokyo issued an apology, suspended the program, and said it would investigate the cause of the seizures.[3] Officers from the Atago police station, acting on orders from the National Police Agency, questioned the program's producers about the cartoon's contents and production process. The Japanese Health and Welfare Ministry held an emergency meeting, discussing the case with experts and gathering information from hospitals. Meanwhile, video retailers across Japan removed the series from their shelves.

Outraged mothers accused TV Tokyo of ignoring their children's health in the quest for ratings; other parents called for the implementation of an electronic screening device to block intense animation. Japanese Prime Minister Ryutaro Hashimoto expressed concern, stating, "Rays and lasers have been considered for use as weapons. Their effects have not been fully determined."[9] While a Nintendo representative quickly explained that the only link between its game and the cartoon was the characters, the company's shares immediately dropped nearly 5% on the Tokyo stock market.[9] TV Tokyo also placed warning labels on all future and past Pokémon episodes. Despite the scare, and buoyed by the show's enormous popularity and revenue-generating capacity before the illness reports, the Pokémon TV program returned to Japanese airwaves in April 1998. No further incidents of collective illness coinciding with the program's broadcast have been reported.

Bright, flashing lights have been known to trigger seizures in epileptics. In 1994, British commercial television advertisements and programs were limited to a rate of three flashes per second.[9] The limit followed a 1993 incident in which a noodle advertisement featuring fast-moving graphics and bright flashes triggered three seizures. After several teenagers had seizures while playing Nintendo video games, the company began including warning labels on much of its software. The notice stated that the games' graphics and animation could cause a shigeki, a strong stimulation resulting in unconsciousness or seizures.

The Pokémon case was of concern and enigmatic due to the large numbers of children reportedly affected and the array of symptoms. Although bright flashes seemed to be the likely culprit, the flashes 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 common in anime, the distinctive Japanese animation technique used in Pokémon (and many other cartoons, such as Voltron, Sailor Moon, and Speed Racer). There was no apparent difference between episode 38 and the other Pokémon episodes. Producer Takemoto Mori had used virtually identical paka-paka in most of the previous episodes, with slight variations in color and background combinations. "During editing, that particular portion didn't call my attention or bother me," he said.[10] All Pokémon episodes were screened before airing, and no problems were reported.

A clear genesis of the Pokémon panic remains elusive. After 4 months, Nintendo announced that it could find no obvious cause for the outbreak, and Pokémon returned to the airwaves. Further research was left to the scientific community. Hayashi et al[11] surveyed patients in the Yamaguchi prefecture (population 1,550,000) and found 12 affected children with no history of epilepsy. During the program, 2 had fainted and 10 had had tonic-clonic convulsions. Eleven of the 12 had photosensitivity or epileptic abnormalities on electroencephalogram. They concluded that the children had latent photosensitive conditions, which had predisposed them to have seizures when exposed to the flashing lights. Hayashi et al estimated the incidence of seizures triggered by Pokémon at 1.5 per 10,000, 10 times the incidence found by British researchers.[12]

Yamashita et al[13] studied all children in 80 elementary schools in the central Fukuoka prefecture on Kyushu Island (population 470,807). On December 22, 1997, 6 days after the outbreak, teachers asked whether any pupils had had symptoms after seeing the Pokémon episode. Questionnaires were also sent to medical facilities in the prefecture. Of the 32,083 enrolled students, only 1 had a convulsion, while 1,002 reported minor symptoms. Since half of all boys and girls saw the program, Yamashita et al[13] estimated that 6.25% of the children were affected. A survey of 12 hospitals in the prefecture found that 17 children aged 2 to 15 years were treated for convulsions. Tobimatsu et al[14] studied 4 children who had been affected by Pokémon and diagnosed photosensitive epilepsy in all 4. They hypothesized that "the rapid color changes in the cartoon thus provoked the seizures."[14] The researchers believe that the children's sensitivity to color, in particular rapid changes between red and blue, may have had an important role in triggering the seizures.

Furusho et al[15] surveyed children who visited pediatric clinics from January 8 to February 28, 1998. Of the 662 children surveyed, 603 (91%) watched the Pokémon episode. Of those, 30 reported complaints: 2 reported seizures, 9 headaches, 8 nausea, 4 blurred vision, 1 vomiting, and 2 each reported vertigo and dysthymia (depression). Sixteen of the children did not have symptoms during or immediately after viewing the program, but much later.


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