Does someone with multiple personalities suffer from schizophrenia?

Entirely Different: Despite the etymology of the term from the greek roots skhizein ("to split") and phren- ("mind"), schizophrenia does not imply a "split mind" and it is not the same as dissociative identity disorder, also known as "multiple personality disorder", a condition with which it is often confused in public perception. Source wikipedia 2012. It is highly unlikely that a person would suffer both.

Schizophrenia : They are not the same thing at all. By definition, schizophrenia is a psychotic disorder. Multiple personality disorder, now properly known as dissociative identity disorder or is one of the dissociative disorders listed in the DSM-V.