Schizophrenia. Conceptual computer artwork of a distorted human face representing schizophrenia. This psychiatric disorder can include disordered thoughts (such as delusions and hallucinations), psychotic episodes (extreme delusions), disturbed moods, an altered sense of self (from withdrawal to a loss of ego boundaries), and a splitting of personality or lack of personality integration. A key defining characteristic of schizophrenia is that it must be a long-term disorder lasting at least 6 months. The cause is unknown, but there is thought to be a genetic predisposition. Treatment includes drugs and psychiatric behaviour therapy.