Multiple personality disorder is known as dissociative identity disorder. There is much disagreement in the psychiatric field as the actual prevalence of this disorder. In its pure form, it is most likely a very rare condition. Symptoms include having different, seemingly unrelated alter egos with different goals and view points. Patients don't tend to realize that the other person even exists. Psychiatric co-conditions often exist including depression. This disorder can only be diagnosed by a psychiatrist
. Unfortunately, there are few clinical diagnoses for people that seem like a different person when they are angry. It may be that you mother is depressed and that one of the manifestations of her condition is wide mood swings. Other possibilities exist but would need to be teased out by a psychiatrist or psychologist
. I suggest you try talking to your mother about these issues directly and ask her to schedule an appointment with her primary care physician
. If he or she diagnoses one of the common mental conditions such as depression she can get the treatment she needs. This may be your best bet. Perhaps her doctor will refer her to a mental health specialist or someone else she can talk to. Good luck.