I'm not sure how to tell for sure if a kid has ADD, but I know how to help prevent it.
Children's brains are developing their neural patterns until the age of 6-8 years. Caffeine, Sugar, and Video Games (all things which stimulate neural activity) can cause those patterns to develop a heightened rate of speed, which makes children unable to control themselves when required to sit still or concentrate on things. I've seen several children that almost live on their gameboys, and when the gameboy is taken away, they are totally unable to sit still or focus.
I don't let my son have caffiene or sugar except on rare occasions (I buy or make everything sweetened with splenda, he doesn't know the difference.) and when he's older, will only let him play educational games, and even then, only if they don't require high speed hand/eye movements that will train his brain to function frantically like the games that most kids play now.
at 11:41 PM on Feb. 14, 2009