I have a 7 year old ds who was given a verbal dx of Aspergers by a Paediatrician in January.
He has been gluten free since last November. We intially went gf with him because of digestive issues, rather than because of his ASD, so haven't gone casein free as his digestive issues all but resolved once we removed the gluten and he/we are vegetarian so going casein free would be a nightmare really.
We definitely noticed an improvement after an initial couple of weeks of hell (think it was withdrawal as he was big on wheat products before) then after about a month we noticed a much bigger improvement.
His eye contact improved a lot, he is much calmer generally, more sociable and demonstrative (hugs etc).
We have also been able to trace back any 'difficult periods' to inadvertent gluten intake so we're pretty sure its working for him.
A few weeks ago I was beside myself because his behaviour seemed to have deteriorated and if anything was worse than prior to the gf diet. Then we realised that we had been inadvertently giving him gluten on a regular basis over a three week period. We eliminated that source of gluten and he settled back down over a period of about two weeks.
The Paed we saw has arranged for him to be tested for Coeliacs in July and unfortunately he needs to have been back on a gluten inclusive diet for at least 3 months prior to the test. So, we have been slowly reintroducing gluten over the past fortnight and it has been awful. Last week he was over emotional (lots of tears and meltdowns and a great deal of extra tlc needed). This week he is struggling with eye contact and we are finding it increasingly hard to get/keep his attention. On top of that he has started bedwetting again this week and he hasn't done that the whole time he has been gf. (I think its due to inflammation of the bowel putting pressure on his bladder.)
To be honest we are at the point of cancelling the test and just keeping him gf, as we can't bear to keep feeding him something that is obviously having such a terrible negative effect on him both physically and emotionally.
The thing is, he's really looking forward to having 'normal food' at his birthday party in April. So now we don't know what to do.
Anyway, sorry for the detour, but in short, yes, in our opinion we have had a really positive result from removing gluten from our ds's diet.
Its not an easy option though. Gf food is really expensive and you have to become an obsessive label reader, as even things like malt vinegar have gluten in, as do some baking powders and other products you wouldn't expect to find it in. We also discovered that our ds reacts to oats as well as grains, which was unfortunate, as he had eaten porridge every morning since he was weaned up until we made that discovery!