Gene expression analyses conducted only in those cytokines that were different in the serum (IL-1α, IL-1β, IL-6, IL-8 and TNF-α) revealed significantly increased mRNA levels of IL-1α (d = 0.6), IL-6 (d = 0.7) and TNF-α (d = 1.6) in first-episode psychosis patients when compared with controls. This evidence concerns the gene IL1A and psychotic disorder.