CXCL8 and schizophrenia: Interleukin-6 (IL-6) levels (7 studies [230 patients]; SMD = 0.55; 95% CI 0.35–0.76; I2 = 1%) and IL-8 levels (3 studies [95 patients]; SMD = 0.46; 95% CI 0.17–0.75, I2 = 0%) were increased in schizophrenia but not significantly increased in affective disorders.