Sometimes a diagnosis is made by a positive response to specific medications, used to treat bipolar, like vonnie says about her own son. A psychiatrist guessed, prescribed the bipolar medications, and voila, they worked. But then to complicate things many medications will work on different symptoms. Even on maladies they were not created for They call this sometimes off label.
When practitioners diagnose they frequently do rule outs. Which is to say for example, rule out psychosis, not otherwise specified. They are saying: prove it is not that.
They are not saying positively it IS one thing or another. Because it is hard to know, often, without a lot of observation
In my experience there can be as many diagnoses as diagnosticians. Unless there is copying going on, one following the other. Or like my son, he tells them something he himself copied from a friend and the psychiatrist writes down what he says.
I am not trying to undermine confidence. But this is not rocket science.
There is a kernel of truth in what you were told. Your experience as a parent is valid. But if you are anything like me, fear and denial undermine "knowing."
If it were me I would TRY to not get hung up on the diagnosis and focus on the behaviors, caring for her and yourself. (But as i said, I get scared, and fixate on what scares me.)
I am a great believer in expressive arts therapies (art, dance, music theater, etc.) , exercise and movement and the outdoors. Equestrian and equine therapy (horses) have been efficacious with the mentally ill young. There are therapeutic riding programs that are free and sliding scale.
Take care. This is very hard. I hope you stay with us awhile for support.