I would look at the two diagnoses and see if they could be complimentary or related; if it were depression and anxiety, for example, I would not have any trouble with a doctor prescribing for what the doctor sees and the therapist working on what they see from their end, etc. To my thinking, nothing is "pure" and simple with only one cause or effect and every little bit helps; I would try the medication and see if you, your daughter, the doctor and the therapist (in that order) believe it helps and is worth while. You know your doctor works well with her therapist so that is not a problem? I don't know that the therapist and doctor have to work together, other than to agree the medication helps your daughter, but you and your daughter will be the best judge of that.