[Schizophrenia in children and adolescents: relevance and differentiation from adult schizophrenia].

Schizophrenia in childhood is rare (point prevalence <1/10,000 before the age of 12) and most often has insidious onset, severe clinical presentation and adverse course and outcome. The incidence of schizophrenia rises dramatically in adolescence, and its prevalence is estimated at 0.23% in the age between 13 and 18 years. The findings from clinical, neuroimaging, neuropsychological and neurobiological studies support that there is a substantial continuity between childhood, adolescent and adult schizophrenia, despite developmental differences. For this reason, the DSM-IV and ICD-10 criteria for schizophrenia are valid for all age spectrums, but their application in earlier ages is difficult, and the particular developmental characteristics of each developmental phase should be taken into consideration. The differential diagnosis of childhood and adolescent schizophrenia, especially from pervasive developmental disorders, affective disorders with psychotic features and some forms of atypical psychosis, poses similar difficulties. The clinical picture is characterized predominantly by auditory hallucinations, delusions which are less complex than in adults, and flat or inappropriate affect. Formal thought disorder and disorganized behavior are common. Premorbid neurodevelopmental impairments, including language, motor and social deficits, are more frequent and more pronounced in persons that will later on develop schizophrenia during childhood or adolescence, compared to adulthood. Furthermore, the emergence of prodromal symptoms, prior to the main psychotic symptoms, is common. The onset of the main psychotic symptoms is usually insidious, and delay in diagnosis and treatment is common, with adverse consequences on the course and outcome of the disorder. The onset of overt psychosis is characterized by a marked deterioration from previous level of functioning in the vast majority of children and adolescents, and an adverse course and outcome is reported in approximately 50-60% of cases. Compared to adult schizophrenia, childhood schizophrenia manifests higher familial predisposition and possibly greater genetic loading. Some of the susceptibility genes that have been detected in adult schizophrenia have also been replicated in childhood schizophrenia studies. Neuroimaging studies in childhood schizophrenia provide evidence for progressive structural brain abnormalities. Patients with childhood onset schizophrenia manifest significant progressive reduction of gray matter volume during adolescence, to a much greater extent than the gray matter reduction normally expected due to brain development in adolescence, which seems to be linked with the reorganization ("pruning') of neural synapses. The convergent data from schizophrenia studies in children, adolescents and adults provide support for the prevailing modern neurodevelopmental theories for the aetiopathogenesis of schizophrenia. The management of schizophrenia in children and adolescents should be based on a multimodal therapeutic plan, including drug therapy and individual psychotherapy, along with family, social and educational interventions.