I came here, also, to comment on complex trauma. However, I have a different take. Formerly traumatized children, even those with treatment-resistant personality disorders, can improve how they work with their system through therapy. Experiential therapies like IFS are proving to be groundbreaking modalities with great outcomes. They also reframe the goal: the goal is not to heal, but to understand, work with, and create space between the self and the system that creates automatic responses to the world at large. In doing so, one expands their window of tolerance over time. I actually found this article to be very inline with trauma healing and my own personal experience of healing complex-PTSD.