A person experiencing untreated schizophrenia is typically characterized as demonstrating disorganized thinking, and as experiencing delusions or auditory hallucinations. Although the disorder is primarily thought to affect cognition, it can also contribute to chronic problems with behavior and emotion. Due to the many possible combinations of symptoms, there is ongoing and heated debate about whether the diagnosis necessarily or adequately describes a disorder, or alternatively whether it might represent a number of disorders. For this reason, Eugen Bleuler deliberately called the disease "the schizophrenias", plural, when he coined the present name.
Schizophrenia is a psychiatric diagnosis that describes a mental disorder characterized by impairments in the perception or expression of reality and by significant social or occupational dysfunction.
Diagnosis is based on the self-reported experiences of the patient, in combination with secondary signs observed by a psychiatrist, clinical psychologist or other competent clinician. There is no objective biological test for schizophrenia, though studies suggest that genetics, neurobiology and social environment are important contributing factors.
Current research into the development of the disorder often focuses on the role of neurobiology, although a reliable and identifiable organic cause has not been found. In the absence of objective laboratory tests to confirm the diagnosis, some question the legitimacy of schizophrenia's status as a disease.
The term "schizophrenia" translates roughly as "shattered mind," and comes from the Greek σχίζω (schizo, "to split" or "to divide") and φρήν (phrēn, "mind"). Despite its etymology, schizophrenia is not synonymous with dissociative identity disorder, also known as multiple personality disorder or "split personality"; in popular culture the two are often confused. Although schizophrenia often leads to social or occupational dysfunction, there is little association of the illness with a predisposition toward aggressive behavior.
Patients diagnosed with schizophrenia are highly likely to be diagnosed with other disorders. The lifetime prevalence of substance abuse disorders is typically around 40%. Co-morbidity is also high with clinical depression, anxiety disorders, social problems, and a generally decreased life expectancy is also present. Patients diagnosed with schizophrenia typically live 10-12 years less than their healthy counter-parts, owing to increased physical health problems and a large suicide rate.