[Presentations and diagnostic criteria of schizophrenia].

Childhood onset schizophrenia is very rare, but it's existence evokes a neuro-developmental hypothesis of a morbid process (genetic vulnerability and perinatal factors), affecting early cerebral development and evolving quietly until post-adolescence when the first psychotic symptoms manifest. The prodromic phase of schizophrenia consists of a constellation of non-specific symptoms, that which renders the institution of early treatment so difficult. The presence of psychotic symptoms in adolescence, even more so than in the adult, is not synonymous with schizophrenia. The appearance of an acute psychotic episode does not automatically prejudge an evolution to schizophrenia. It is the clinical investigation over several weeks that gives a diagnostic and therapeutic orientation. The existence of proven positive symptoms and the evolution of negative symptoms, despite a supportive environment and treatment, provide the best diagnostic arguments.