The book contains a literature review, the symptoms, the subtypes, the causes and the case conceptualization of schizophrenia disorder. More specific, it was examined the effect of behavioral treatment on the 295.30 Paranoid type of Schizophrenia disorder. The main hypothesis was that the behavioral model can be applied in the treatment of 295.30 Paranoid type of Schizophrenia disorder. The patient who participated and received treatment based on the behavioral model was hospitalized at a private psychiatric hospital at Athens, Greece. The examiner had weekly sessions with the patient and applied the appropriate behavioral techniques under the supervising of the therapists who were working at the psychiatric hospital. At the end of the treatment''s application, the patient''s clinical condition revealed that the original hypothesis was supported. Therefore it was proved that the application of the behavioral model in the treatment of 295.30 Paranoid type of schizophrenia disorder have a positive outcome.