In the 1980s, paranoid personality disorder received little attention, and when it did receive it, the focus was on its potential relationship to paranoid schizophrenia.
Another criterion present in patients with paranoid schizophrenia are auditory hallucinations, in which the person hears voices or sounds that are not really present.
There are many different types of disorders that have similar symptoms to paranoid schizophrenia, and doctors diagnosing patients can sometimes make mistakes.