Schizophrenia is a term for a set of disorders characterized by distortions of thinking and perception, as well as inappropriate or flattened affect. The disorder was formerly called dementia praecox, and was renamed schizophrenia by the Swiss psychiatrist Eugen Bleuler in 1908 (1).
Symptoms of schizophrenia are categorized as positive i.e. hallucinations, delusions, disorganized speech, grossly disorganized or catatonic behavior, and negative, i.e. blunting of affect, loss of volition and alogia (poverty of speech).
See schizophrenia in ICD-10
1. Kyziridis TC. “Notes on the history of schizophrenia“. German J Psychiatry. 2005;8:42–8.