Total RNA was isolated from approximately 50 mg homogenized tissue in Trizol using the RNeasy kit according to manufacturer protocol. Samples were processed in batches of 12, and the Pitt matched case/control pairs were always processed in the same batch. The order of extraction for SCZ-affected and control samples was assigned randomly with respect to brain bank, diagnosis, and all other sample characteristics. Because the affective disorder cases (AFF) and matched controls from Pitt were not available until after the processing of the SCZ and controls was underway, these samples were randomized among the remaining 132 SCZ and control samples still queued for extraction at that time. The mean total RNA yield was 15.3 ug (+/− 5.7). The RNA Integrity Number (RIN) was determined by fractionating RNA samples on the 6000 Nano chip (Agilent Technologies) on the Agilent 2100 Bioanalyzer. 51 samples with RIN < 5.5 were excluded from the study (see Sample QC below). Among the remaining samples, the mean RIN was 7.7 (+/− 0.9), and the mean ratio of 260/280 was 2.0 (+/− 0.02).
