Most cult experts agree that cult mind control creates a new cult identity in addition to the real identity. However, it is important to notice that Dissociative Disorder (DSM 300.15) created by cults is different from Multiple Personality Disorder (DSM 300.14) caused by psychological trauma. People who have MPD have different personalities that do not know about existence of one another and a person does not remember what they did being in another personality. Members of cults know about their different personalities and remember what they did in another personality.
There are different concepts of what a person should do after leaving a cult. Some cult experts stress that a former member of a cult should leave the cult pseudo-identity and come back to the real identity. Some say that the cult identity should be split into sub identities and integrated into the real identity. Robert Jay Lifton in Thought Reform and the Psychology of Tolalism: A Study of "Brainwashing" in China wrote that after brainwashing people "experimented" with their identities and sub identities. They gained some sub identities that they did not have.
I think the model of postcult identity is:
1. The real pre-cult identity as the basis
2. Some sub identities of the cult identity integrated into the real identity
3. Some new sub identities developed after the cult and integrated into the real identity
A person can develop new sub identities before the cult sub identities are completely integrated into the real identity which becomes the leading part of the post-cult identity.