Schizophrenia is a major mental disorder with an onset in late adolescence and early adulthood. DSM-IV (APA 1994) diagnostic criteria include the presence of psychotic symptoms (delusions and/or hallucinations) and social dysfunction for a period of at least six months. Early-onset schizophrenia (EOS; onset between the ages 13 and 18 years), although a relatively rare disorder, is associated with a proportion of offending and violent crime. A birthcohort study (Arseneault et al. 2000c) suggests that schizophrenia spectrum disorders account for 10% of the total violent crimes committed by youths up to the age of 21.