I haven't read anywhere about putting an ADHD child on a Celiac diet, but it makes sense. Austic children can respond well to a Celiac Diet.
I asked about soy milk, because I stopped nursing my 7 year around three months. He was a fussy baby and never nursed well and when I stopped he broke out in a rash with regular formula. I switched over to soy formula and the rash went away.
I'll do some research on my own and see if I can come up with info.