sounds like she is having symptoms of a dissociative disorder. There are a few different kinds of dissociative disorders, though i forget what they are all called.
anyways, dissociative disorders are usually the result of something very stressful or traumatic that happened durring someone's life( like being attacked, raped, abused, etc.). The dissociative disorder might not develope until years and years later, but things like depression, anxiety, panic attacks, Eating disorders, PTSD, are also often present along with a dissociative disorder.
good luck
-Becka