The nosology of schizophrenia: toward DSM-5 and ICD-11.

Although dementia praecox or schizophrenia has been considered a unique disease entity for more than a century, definitions and boundaries have changed and its precise cause and pathophysiology remain elusive. Despite uncertain validity, the construct of schizophrenia conveys useful clinical and etiopathophysiologic information. Revisions of the Diagnostic and Statistical Manual of Mental Disorders and the International Classification of Diseases seek to incorporate new information about schizophrenia and include elimination of subtypes, addition of psychopathological dimensions, elimination of special treatment of Schneiderian "first-rank" symptoms, better delineation of schizoaffective disorder, and addition of a new category of "attenuated psychosis syndrome".