The word "schizophrenia" comes from two Greek words that mean "to split" and "mind," because there is a 'split' between what's going on in the person's mind and what is actually happening. A person with schizophrenia does not change between different personalities: they have only one. The condition in which a person has more than one personality, meaning they act like a different person at different times, is dissociative identity disorder. There are no medical tests that can be used to say if a person has schizophrenia or not, so getting a diagnosis depends on which list of symptoms are used. It also depends on the doctor or psychologist who talks to the person. The lists of symptoms include wording like "Disorganized [not organized, or oddly organized] speech present for a significant portion of time". It is difficult to agree on what exactly "disorganized speech" is and how disorganized it has to be. It is also difficult to agree on how long a "significant portion of time" is. Because of this, two doctors or psychologists trying to make a diagnosis may often disagree. One will say that the person is schizophrenic and the other will say he or she is not.