Pokémon contagion: photosensitive epilepsy or mass psychogenic illness?

We studied a reported illness outbreak occurring on December 16, 1997, involving more than 12,000 Japanese children who had various signs and symptoms of illness after watching an episode of a popular animated cartoon, Pokémon. While photosensitive epilepsy was diagnosed in a minuscule fraction of those affected, this explanation cannot account for the breadth and pattern of the events. The characteristic features of the episode are consistent with the diagnosis of epidemic hysteria, triggered by sudden anxiety after dramatic mass media reports describing a relatively small number of genuine photosensitive-epilepsy seizures. The importance of the mass media in precipitating outbreaks of mass psychogenic illness is discussed.