Schizophrenia is a serious and chronic medical condition. It is a disorder of the message system in the brain. Someone with schizophrenia loses the ability to act properly or to think clearly – his or her mind is "split from reality" (hence schizo "split" and phrenia "mind" from ancient Greek). The term schizophrenia does not refer to multiple personality disorder.
Schizophrenia affects about 1% of people throughout the world. It sometimes starts during childhood, but most often shows up in the late teens or 20s.
It can develop gradually, over the course of weeks or months, or it can seem to come on very suddenly. The signs of schizophrenia are easy to misunderstand, and can sometimes be frightening to other people. While this disorder never goes away, it can often be managed with proper medical care and family support.
We do not yet know what causes schizophrenia. There are many theories, but it is most likely a result of genetic factors that trigger complex changes in the brain's chemistry and structure. Research has demonstrated that people with schizophrenia have changes in brain function and anatomy. But it's not clear whether schizophrenia is a single disorder or a number of "syndromes" with different causes.
Some experts believe that the condition is triggered by stressors (e.g., substance misuse, stressful life events) in people whose brains are predisposed.