Schizophrenia is a condition which may be diagnosed by a psychiatrist. It is mental illness where people may see, hear or believe things that are not real. It can be a big problem for people who have it. Some similar mental illnesses include schizotypal personality disorder, schizoaffective disorder, and schizoid personality disorder.

It is a relatively common condition affecting one in 200 people. It is not infectious in any way. There is a danger that the sufferer may self-harm. Its cause is not exactly known. Very often it first appears in teenage years when the sufferer goes through puberty. There is no cure, but there is treatment which can help most of the sufferers.

People with this disorder often do not behave the way most people do towards others. They also may not know what is real (this is called psychosis). Some common signs are strange beliefs, unclear or confused thinking and language, hallucinations (such as hearing voices that aren't there), poor interaction with others, less expression of feelings, and not doing much. They also may not care about many things.

Schizophrenia is a chronic condition. As of 2021, there is no cure, but a combination of a therapy and certain drugs can allow most people suffering from it to lead a normal life.