If your child is between 6 and 18 years old and a mental health professional thinks your child had schizophrenia before his/her 13th birthday, you child may qualify for a study being conducted by the Child Psychiatry Branch. We are looking for children who, before their 13th birthday, had severe hallucinations (voices/visions) and other psychotic symptoms which made them act very different from other children. This inpatient study tries to understand the causes of severe hallucinations (voices/visions) and other psychotic behaviors; the study offers treatment with a comparison of two drugs used to treat psychosis: Clozaril (clozapine) and Zyprexa (olanzapine). This drug trial begins with: 1) 3 weeks of evaluation and extensive testing while the child is on the medications they were on at admission 2) gradual decrease of medications 3) up to 3 weeks without any medication to help the staff be certain of the diagnosis. At the end of this time, if the staff diagnoses your child with childhood onset schizophrenia, then the child is put on 8 weeks of either clozapine or olanzapine and maybe another 8 weeks of whichever medication (clozapine or olanzapine) the child did not receive during the first 8 week period. Research participation and medication is free of charge; transportation and housing are provided to parents. To find out if your child qualifies or for more information, please call (301) 496-5645 or email us at nimhcore@mail.nih.gov.