This single-case experiment evaluates the impact of an innovative rational-emotive cognitive treatment focused on hallucination and delusions on quality of life, depression, anxiety, and insight in a female patient suffering from schizophrenia. The cognitive treatment developed for this experiment was directly inspired by the work of Ellis and Chadwick, Birchwood, and Trower. The rational-emotive cognitive approach used in the present study effectively reduced the patient’s anxiety and depression, increased the patient’s overall quality of life and insight. The gains were maintained at 3-month, 6-month, and 12-month follow-up. Future investigations into treatments for psychosis should focus on patients’ insight regarding the origin of their hallucinations. Further, the link between negative and positive psychotic symptoms should be explored.