Patients with COS were recruited through nationwide referral and extensive prescreening. Diagnoses were made using unmodified DSM-IIIR/IV criteria for schizophrenia with the onset of psychosis before age 13. Any history of significant medical/neurological problems, substance abuse, or premorbid IQ below 70 was exclusionary. Full, non-psychotic siblings (SIBs) of COS subjects also participated in the study and were scanned prospectively along with probands, at approximately two-year intervals. The SIB group showed no evidence of schizophrenia spectrum disorders for either Axis I (mental illnesses) and Axis II (personality disorder and “mental retardation”) diagnoses (Gogtay et al., 2007). We included all COS probands and SIBs with DNA and at least one MRI scan resulting in 83 COS probands and 62 SIBs with a total of 193 and 124 sMRI brain scans respectively. The institutional review board of the National Institutes of Health approved the study and written informed consent and assent were obtained from parents and children respectively.
