Factor_x55: At our school they say that even if you are defending yourself that you will get suspended for being in a fight. But even though they say that, the defender never does get suspended.
Also, the Australiqan law on this topic clearly states that if someone attacks you, it is perfectly legal to use equal force on them in return.
Eg: If they hit you, you can hit them, if they don't do anything, you can't do anything, if someone uses a weapon, or produces one with the intention of using it, you are legally allowed to use a weapon in return as much as you like.
MorphBall360: I believe corporal punishment isn't the answer for general mis-behaviour. It should only be used for bullying (the punishment fits the crime).
On a general note, I don't think ADD should be an excuse to let someone get away with beating someone up. They should still get punished all the same. After all, there is medication for ADD, and if the kid doesn't take it, sucks to them.