Schizophrenia starting before age 18 represents a more severe illness with significant functional impairment and worse response to the usual antipsychotic medications. There has been a review of research regarding the efficacy and safety of antipsychotic medications in the treatment of children and adolescents with schizophrenia. This found that antipsychotic medications were effective for psychotic symptoms. And, clozapine was found to be superior to haloperidol and olanzapine. Child-onset schizophrenia (occurring before age 13) is extremely rare. Few research trials of antipsychotics have been done in child-onset schizophrenia. Onset of schizophrenia after age 13 is more common. Research supports clozapine use for adolescent schizophrenia. There are not unique safety concerns with clozapine in people younger than 18, except for children under 13, for whom akathisia has been seen. Weight gain is a greater problem in youth taking antipsychotic medication, including clozapine. Some recommend starting metformin prophylactically with clozapine in this population. Titration of clozapine in adolescents should be based on tolerability. A starting dose of 0.3 mg/kg has been recommended, not to exceed 25 mg total.