From what I have read, multiple personality disorder is most common in very intelligent women who were both sexually and physically abused from an early age, over a long period of time. I was abused from an early age, over a number of years. When I began therapy in my twenties, I would dream of six sisters, each was an age at which I had been particularly traumatized. Over time, some of the dream sisters melded together and I dreamed of four sisters. I eventually dreamed of conceiving a child -- conceiving a new self.
I was in my late thirties when I stopped feeling fragmented, when I finally felt whole. I never had separate personalities, but I suspect the abuse I endured stopped short of producing MPD. I wasn't splintered to that degree.
I have two special needs sons. I always told them their traits had good points and bad points. I did not communicate to them that they were disordered. I believe it helped them deal constructively with being different and helped them not feel broken or stigmatized. So I have sympathy for the point of view that multiples are just different and not disordered, though I feel clearly that my sense of having various personas was rooted in trauma and I feel clear that healing my trauma is what made me feel whole and unfragmented. So I find the idea that there are people who are multiple who do not view it as a disorder intriguing.