A study in the "Journal of the American Academy of Child and Adolescent Psychiatry" found that kids who had been drinking three cans of caffeinated soda per day experienced caffeine withdrawals. When the kids went off the sodas cold turkey, their performance dropped dramatically.
So what can you do?
1. Limit your child to one soda a day. When you figure one soda, keep in mind other sources of caffeine the child is having during the day, like chocolate, iced tea, etc.
2. Just like you wean adults off drugs, wean a child off excessive caffeine gradually.
3. You can begin to substitute fruit juices for sodas.