Schizophrenic :



In popular usage, schizophrenic (and the more slangy and now dated schizoid) indicates split between two attitudes.



This drives people with training in psychiatry crazy.



Schizo- does indeed mean split, but it is used here to mean split off from reality.



Someone with a Jekyll-and-Hyde personality is suffering from multiple personality disorder (or, more recently, dissociative identity disorder), not schizophrenia.