IL6 and schizophrenia: IL-6 is one of the most extensively investigated cytokines in schizophrenia research, and with the exception of the meta-analysis by Miller et al., which reported its unaltered levels in SCh patients [12], there are consistent reports of elevated peripheral and CSF levels compared to HC in all patient populations [13,14,41,42,43], including chronic EOP, CHR and UHR patients [38,39,40].