We saw our DAN doctor and had our son tested. He showed signs of heavy metals. We started our first round of DMSA just last week and wow! What a change. He started to asks for things without a prompt. I was rather surprised at how quickly the response was with our son. We are testing his urine to see the results, but already I'm convinced that this is working for us. We also have been on the GFCF diet for at least 6 months and our son check clear for bad bugs in the gut. I think that is very important that your child has a healthy gut before starting.