How well do patients maintain their anxiety and depression symptoms after cognitive behavioral therapy? Do they need regular follow-up visits or consolidation treatments?
This is the sort of question that you are better off answering for yourself by doing a literature search. It's unlikely that anyone here has such a search to hand, and your question will at most attract a few papers that may not represent the sum of knowledge in the area.
I would check the Cochrane collaboration first – your question may be answered there,