Schizophrenia is having more than one personality, isn't it?
No; it's been referred to as "split personality," but it's NOT in the sense of multiple personality.
It's a brain disease/mental illness in which the individual loses touch with reality; there is psychosis, which may be marked by visual, auditory, olfactory, or other sensory hallucinations.
If Jodi Arias had schizophrenia, and in the midst of a psychotic episode, the trial would have been a very, very different trial; when one is psychotic, intent cannot be formed. We'd be looking at "guilty but insane," or "not guilty by reason of insanity," depending on how AZ rolls with insanity defenses.