Schizophrenia is a major public health problem throughout the world.
The prevalence of schizophrenia worldwide appears to be slightly less than 1 percent, although pockets of higher or lower prevalence have been identified. In the United States, people with schizophrenia occupy about one fourth of all hospital beds and account for about 20 percent of all Social Security disability days. Schizophrenia is more prevalent than Alzheimer's disease, diabetes, or multiple sclerosis. A number of disorders share features of schizophrenia. Disorders that resemble schizophrenia, but in which symptoms have been present for less than 6 months, are called schizophreniform disorders.