What PDT does - well, I found this website really informative: About Psychotherapy
My therapist works rather a lot on these lines. My exT didn't, even though I think she was mostly psychodynamic as well - she did tell me things like "just do it", which my current T would never do. Sure, patently harmful behaviours have to be addressed quickly. But when it comes to changing long-term behaviour, the PDT approach of understanding underlying causes works better for me. Not for everybody, I know that. But for me, it's better.