Today's installation in The Definitive Clearing Up of Basic Psychology Terminology is dedicated to schizophrenia.
Schizophrenia is a psychological disorder marked by the inability to distinguish between fantasy and reality. Delusions, whether they be visual or aural are common in schizophrenics. They may believe that they are being followed, and are often highly suspicious and untrusting of others, assuming that people are plotting against them.
A schizophrenic does NOT have multiple personalities. That is Multiple Personality Disorder (or Dissociative Personality Disorder? I can't actually remember the exact name of it so I'll just call it Multiple Personality Disorder for now.) There is still debate amongst psychologists if Multiple Personality Disorder actually exists - if it's actually possible for one person to house two or more distinct personalities that are entirely independent of one another.
It may seem like a schizophrenic person has multiple personalities on occasion, if they are in a delusional state that, for example, has made them suddenly and severely afraid for their lives. They will be acting distressed and panicked and will not listen to your reason, much like any person might if they honestly and truly believed that they should be afraid for their life. These are not distinct and independent personalities, but extreme delusional beliefs.
Similarly, If you see a schizophrenic person having a conversation with themselves, they are not having a conversation with one of their separate personalities, but probably with external voices that they are hearing.
So next time you refer to a real or hypothetical person as schizophrenic, make sure you don't mean to say that they have multiple personalities.
Thanks! This has been an episode of The Definitive Clearing Up of Basic Psychology Terminology.