One is paranoid schizophrenia. The other is paranoid personality disorder. Sometimes medical problems and medicines can make people paranoid. Marijuana, cocaine, PCP, and certain prescriptions can do this to some people. If someone is very confused, he or she may get paranoid too.
Schizophrenia is a mental disorder in which people are no longer dealing with reality.
They may hear voices that are not there. They may have strange beliefs about things that are not true. They may hear voices saying bad things about them or the people they care about. The voices may tell them that they are bad or that they are going to hell. The voices may tell them that the people that they love are doing bad things or that they are in trouble.