Schizophrenia and related psychotic disorders—delusional disorder, brief psychotic disorder, schizophreniform disorder, schizoaffective disorder, and schizotypal personality disorder—are mental illnesses that are characterized by various types of symptoms, which are called psychotic symptoms, negative symptoms, and cognitive dysfunction.
The term psychotic implies some degree of loss of contact with reality. The word schizophrenia means, literally, "split mind," and was created based on the idea that different parts of an individual's personality, such as thought, emotion, and perception, had become fragmented or split.
Psychotic symptoms include hallucinations, delusions, disorganized thinking and speech, and disorganized (bizarre and inappropriate) behavior. This may include catatonia, a state of abnormal behavior and reduced or increased movement.
Negative symptoms are a noticeable decrease in or lack of normal thoughts, emotions, and behaviors. For example, people may lack motivation and their face may not express emotions.
Cognitive dysfunction refers to problems with thinking (cognition), such as being able to focus one's attention, remember things, have self-control, and think flexibly.
Diagnosis and treatment of schizophrenia and related psychotic disorders are based on symptoms and the course of the specific illness.
