[Functional psychosis in childhood and adolescence].

OBJECTIVE To review the literature about functional psychosis in children and adolescents, allowing pediatricians to recognize the pathology in their daily work routine. SOURCES OF DATA Classical textbooks of child and adolescent psychiatry; search of MEDLINE and Lilacs databases (1993 to 2003). Computerized search methods were combined with manual search of the literature. SUMMARY OF THE FINDINGS This article is structured in topics, trying to define and classify psychosis in childhood and adolescence, with schizophrenia being the main disorder. The article stresses the difficulties for the diagnosis in children, and addresses the main treatment guidelines. CONCLUSION Schizophrenia beginning in childhood, or very-early-onset schizophrenia, is a very rare pathology, almost 50-fold less frequent than early-onset schizophrenia (appearing at age 15 or later). Childhood-onset schizophrenia is a separate disorder, different from infantile autism, not only in terms of conceptual issues, but also in terms of phenomenology, genetics and associated clinical and neurological issues.