Individuals having PTSD , acute stress disorder, dissociative amnesia and DID may experience to forget certain events thus here defence mechanism of denial , suppression and fantasy is being utalized inorder to deal with traumatic intrusions. So, age regression can enable an individual to restructure those false memories, to induce positive memories and restructure the aspect of trauma.
Example:
I have seen this type of induction in netflix series Freud when, Fleur ( a girl having DID) is taken back to the place where she experienced trauma in order to restructure the context of trauma.