L.
I have a RAD daughter, she was treated but never really got better. If there is some intervention while the child is young, there is often a good result, but we never knew what was wrong with this child until she was ten, so even though she is fragilly attached, her wierd behaviors continue into adulthood. Now they call it borderline personality disorder.
I read the one answer you recieved and wanted to say that it is NOT necessarily the fault of a non-caring mother. My daughter was adopted and her disorder was probably caused by repeated breaks, but I know of other unattached children who had loving caring mothers who did all they could and still the child failed to attach.
There is tons of information out there on RAD, a good place to start is ATN.com Attachment and Trauma Network.