Because that is what CAMHS are now offering for my 8 year old DD who has just been diagnosed with ASD (HFA for what the term is worth). She already has a diagnosis of selective mutism. I am pretty clueless at how psychotherapy will work as it is very unlikely that DD will speak at all... On the other hand I was not at all keen to do 'family therapy' which was offered last year when older DS got his ASD diagnosis. Managed to turn that into CBT for DS, which obviously wouldn't work for DD.
DD is very anxious and I don't know whether it is a risk that psychotherapy would just increase her anxiety - although I realize that's not 'meant' to happen!