I haven't had much experience with children, but I've been working with developmentally disabled adults for a very long time.
I can tell you that when you get the right mix of medication, it really does help. The persons quality of life is improved and they enjoy life more. The problem is that it usually takes years of trial and error to find the right mix. When you finally do find the right mix, a new medication is released and they have to start all over. It is a vicious cycle.