I was trying to find another article on this that I had recently read, that talks about giving a kid with ADHD a coke or a cup of something with caffeine in the morning; how it actually will help them with focus.
I'm not an advocate of doing this. Yet, when our children have a coke in the morning, I can see them begin to focus a lot better. It all makes sense now, especially since I have learned that ADHD patients are often times treated with stimulants.
Here are a couple of links on this: