from what you know about your narc, can you pinpoint when their breaking point was?

from what i’ve learnt about narcs, it’s that childhood trauma plays a heavy part in their development and what i’ve seen a lot of people say is that it’s a stunted type of growth - that at some point they stay where they are and never move on or grow, just an angry child. i’m intrigued to know if other people have figured out their own parents, i’m still figuring out mine. from what you know about your nParent, do you know what happened to them or how they ended up this way?