United States Patent No. 6,935,954: Sanity System for Video Game
Issued August 30, 2005, to Nintendo of America, Inc.

This patent by inventors from Nintendo of America Inc. discloses a video game system that modifies, monitors, and reacts to a game character’s sanity level. A character’s sanity level is modified by an amount based on the player character’s reaction to a particular occurrence or event in the game. In addition, game play and in-game effects may also change based upon a character’s sanity level. The sanity level of the suspicious Link-looking character in the figure, for example, may not be affected as much since a well-prepared warrior with shield and sword in tow will likely not be intimidated by an otherwise terrifying flying skull with bad teeth. Or the character may have been on the brink of insanity to begin with (after scouring Hyrule unsuccessfully for his lost princess) and the flying skull is actually part of his hallucinations. Now, if only people can monitor their sanity levels in real life…

Exemplary Claim:
A method of operating a video game including a game character controlled by a player, the method comprising:
a) setting a sanity level of the game character;
b) modifying the sanity level of the game character during game play according to occurrences in the game, wherein a modifying amount of is determined based on a character reaction and an amount of character preparation; and
c) controlling game play according to the sanity level of the game character, game play being controlled at least by varying game effects according to the game character sanity level.