Failure of two prior trials with antipsychotic medications (either typical or atypical) used at adequate doses (greater than or equal to 100 mg/day in chlorpromazine equivalents) and for adequate duration (at least 4 weeks, unless terminated due to intolerable side effects). Failure is defined as either insufficient response with persistence of symptoms significantly impairing child's functioning, according to child's and parental reports and medical and school records, or intolerable side effects to drugs other than clozapine and olanzapine.