Schizophrenia affects about one percent of all people. Schizophrenia affects individuals who span the full range of intelligence and education, from the most intelligent to the most simple minded.
No cultural group is immune to schizophrenia, but the content of delusions varies in different parts of the world, according to one study. In Europe, people with schizophrenia were more likely to have delusions of poisoning or religious guilt, while in Japan the delusions most often were related to being slandered.
A person is at higher risk for developing schizophrenia if they:
- Are a male between the ages of 15 and 24
- Are a female between the ages of 25 and 34
- Have a close relative with the illness
- Had a medical problem surrounding their birth
Schizophrenia runs in some families. A person with an immediate family member who has schizophrenia has a 10 percent chance of developing it, and a 40 percent chance if the illness affects both parents or an identical twin.