A mental illness characterized by disordered thinking, delusions, hallucinations, emotional disturbance, and withdrawal from reality.

Some experts view schizophrenia as a group of related illnesses with similar characteristics. The condition affects between one-half and one percent of the world's population, occurring with equal frequency in males and females (although the onset of symptoms is usually earlier in males). Between 1 and 2% of Americans are thought to be afflicted with schizophrenia—at least 2.5 million at any given time, with an estimated 100,000 to 200,000 new cases every year. Although the name "schizophrenia," coined in 1911 by Swiss psychologist Eugene Bleuler (1857-1939), is associated with the idea of a "split" mind, the disorder is different from a "split personality" (dissociative identity disorder), with which it is frequently confused. Schizophrenia is commonly thought to disproportionately affect people in the lowest socioeconomic groups, although some claim that socially disadvantaged persons with schizophrenia are only more visible...