i don't have a link right now, i can get one later, when i get home again. But it was a study done by the American Dentistry Association or whatever XD and the scientist found that it caused "ADHD-like symptoms" in their subjects, mainly rats or mice. But they could have tested it on human children, i don't remember. I do remember that this scientist advised against fluoride since it has NO systemic value, questionable topical value and is, in fact, toxic and harmful....but they fired her. hah and went ahead with it anyways for various reasons. i think the dumbing down/ADHD is just a happy side-effect in their eyes....but I don't think thats why it was started. who knows though. I heard it had more to do with what they should do with toxic waste, the fluoride, and somehow found a way to make it legal to dumb in the water. hahaha i could be off base on the last part, but i think that i heard something of that nature.....