In 1860, Bénédict Morel introduced the term dementia précoce and Langdon Down provided  in 1887 the most complete description to that date of the clinical manifestation that Charpentier described in 1890 as dementia précoce simple des enfant normaux.The description of simple schizophrenia is inter-changeable with describing symptoms as a form of dementia praecox known as simple dementing, at least in the time when the Swiss psychiatrists Otto Diem and Eugen Bleuler were studying it. In 1893, Emil Kraepelin considered there were four types of schizophrenia, and was amongst the first to identify three of them (dementia hebephrenica, dementia paranoides, dementia catatonica). The simplex type was added by Eugen Bleuler to the earlier ones identified by Kraepelin in 1899 and subsequently given a basic outline in 1903 by Otto Diem publishing a monograph on dementia praecox in the simple dementing form. This was based on a survey of two males having had a relatively normal childhood but who then fell into patterns of living tending towards vagrancy.A description of a cerebral disorder in relation to organic factors and in the context of general paralysis of the insane only; with no reference to schizophrenia, shows a disorder with features of generalized dementia (Lishman 1998). In 1951, a film was made showing the clinical characteristics of simple-type schizophrenia. Controversy
Definition of this type of schizophrenia is without unity or is controversial. The diagnosis was discontinued in the DSM system, although it was recommended for reinclusion in 1989.
It was subsequently confirmed as having imprecise diagnostic criteria based on collective descriptions lacking in agreement.However, in an experiment with a small sample size, five patients with a diagnosis of simple deteriorative disorder (DSM-IV) were found to have grey matter deficits, atrophy and reduced cerebral perfusion in the frontal areas. Whitwell et al. found justification to retain the classification on the basis of fulfillment of "dimensional" considerations of classification, as opposed to criticisms resulting from disagreement in considerations of classification using orientation from other categories. References


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