Hi Dr. Tanasugarn - you might consider a book on this topic of understanding people with personality disorders as age regressed. If it's not used as a put down: "you're being childish" but rather, a positive frame - "how beautifully childlike" - it could be a powerful contribution for treatment of people who are so often seen as difficult and untreatable.

I won't repeat it here, but I described at some length, in another comment, how this applies to a family member. It would have been ENORMOUSLY helpful for me to read such a book years ago when I first encountered her, and nobody really understood how to diagnose her.