you not having alters as a child isnot a diagnostic criteria per se, you see with DID there is something called co consciousness. this is having awareness of alters. some people are not aware that they have alters when they are children, example I never knew as a child my alters were there and that they were constantly taking over control. having co consciousness is not a requirement for having DID.

the basics of DID is that the alters are created in children under the age of 5 when the child undergoes extreme trauma (NY mental health demographics\statistics)

each persons internal system of alters is set up according to what that person and all inside needed to survive....

example because I was sexually abused as a child, during those abuses alters were created to handle sexual situations because I was not able to understand and handle adult sex when I was just a child of 4. my brain was just not mature enough to handle that.

in order for me to survive it was best that I not have access to the facts ie the trauma/abuse therefore my system was set up so that I had no co consciousness (awareness) of that trauma and the subsequent alters that were created to handle that.

with me there was an original (host, person born to this body) for some people the trauma's are so severe that their original (host person born to the body ) becomes so traumatized/damaged that they have become so dissociated from the body and system either they are buried so deep none of the alters realize this original person exists or the original has been so dissociated that their mind is in so many dissociated states of mind\fractured (alters).

As for set in stone do you mean the diagnostics/ what DID is/ this special type of alters that come with DID...?

here in the USA some things about DID are set in stone simply because of documented cases of known people in treatment for DID over decades and decades of documentations. its like how the center for disease control can say what diseases are communicable (passed from person to person) because they have documentations to back that fact up. the american mental health system (american Psychiatric Association) puts things in stone like diagnostics and such because of the past history of documentations on the mental disorders. each USA state, and mental agency and hospital keeps files /records\ statistics on each person they treat and each mental disorder they treat. this goes into a big database and then periodically the APA updates their diagnostics and such on mental disorders based on these years of documented cases\statistics.