Let's all take a breath and bask in this great news - a third party doc. This is huge.
Acc. to my quick search of Dr. Tellefsen, it looks like she's employed at Mercy Medical Center now. For those outside the Baltimore area, this hospital operates a lot differently. For one thing, they aren't just psychiatric (though Tellefsen is a psychiatrist). This is a world-class, top-rated facility, and they'll only hire the creme de la creme. She is a seasoned professional, been in practice 31 years. So, not some wet-behind-the-ears novice shrink - she's not being paid to cater to Catherine's feelings. Of course, she's going to work with Catherine to get something resembling competency to stand trial. But you know what I mean... She's objective. Capable.
I can understand how many might think that anyone who was once affiliated with Perkins is somehow "tainted"... But consider this: we don't know why she quit as director. Maybe, just maybe, it was due to dissatisfaction with how things were being run there.