A gradual build-up of symptoms may or may not lead to an acute or crisis episode of schizophrenia. An acute episode is short and intense, and involves hallucinations, delusions, thought disorder, and an altered sense of self. Sometimes schizophrenia has a rapid or sudden onset . Very dramatic changes in behaviour occur over a few weeks or even a few days. Sudden onset usually leads fairly quickly to an acute episode.
Some people lead relatively normal lives between episodes.
Others find that they are very listless. In some, the illness may develop into what is known as chronic schizophrenia . This is a severe, long-lasting disability characterized by social withdrawal, lack of motivation, depression, and blunted feelings. In addition, moderate versions of acute symptoms such as delusions and thought disorder may be present in the chronic disorder. This can be confusing.