Playing and watching mah-jong can trigger epileptic fits in susceptible people, and the only cure for the condition is to give up playing, according to a paper published in the August 2007 edition of the Hong Kong Medical Journal.
In Mah-jong–induced seizures: case reports and review of twenty-three patients the authors describe three Hong Kong cases, all of them involving adult men, and another 20 cases from Taiwan where the patients suffered an epileptic fit brought on by playing mah-jong. In all the Hong Kong cases drug treatment for epilepsy did not cure the condition but when the patients gave up playing mah-jong, their seizures ceased.
Mah-jong is a cognitively demanding game involving substantial higher mental processing and outputs: memory, concentration, calculations, reasoning, strategies, sequential thinking and planning, consideration of alternative solutions, and a lot of decision-making. For this reason mah-jong–induced seizures are best classified as a subtype or manifestation of cognition-induced epilepsy. Other terms used for this group of reflex epileptic syndromes include 'reflex epilepsy induced by thinking and spatial tasks', 'epilepsia arithmetices', and 'decision-making epilepsy'. In this group of reflex epilepsies, the provoking event usually consists of three components: thinking, a visuospatial task, and a manual task, which interact in a complex manner.
Typical seizure-triggers in decision-making epilepsy include chess and card games, other strategic board games, such as Mastermind and checkers, performing complex calculations, drawing or copying geometrical figures, and manoeuvring the Rubik's cube. 'Video-game epilepsy' is classified under a separate category because most cases involve light or pattern-sensitivity in addition to the cognitive component.