The common method of being Knocked Out is by taking too much damage from a fistfight or by weapons. However, Knockouts can also occur when falling from a great height. Technically, being Busted can be considered to be a knock out, due to possessing similar effects afterward, though being Busted has more severe repercussions.
If Jimmy is knocked out, he is transported to the nearest Medical Center or the Boys Dorm (If you are in the Dorm at the time). He will lose items such as Firecrackers, stink bombs, and other weapons once he is knocked out.
If an NPC is knocked out, he or she will remain lying down on the ground until they eventually fade away. While any NPC is knocked out, Jimmy has the option taunting them with "That was easy" and "You're not looking so cool right now," or kicking them although this will still affect the trouble meter. e.g. kicking a knocked out adult will result in Jimmy's trouble meter being raised to the maximum level. Should an NPC knock someone else out, whether it is Jimmy or another NPC, they may taunt them. Jimmy can also taunt a knocked out person even if he is not responsible for it. Dogs have health bars but can never be knocked out no matter how low their health bars are, making them the only NPC that cannot be knocked out.
Any mission that Jimmy was doing prior to being Knocked Out will instantly be failed.