Elevated serum concentrations of IL-6 and CRP in childhood/ adolescence are associated with increased risks of psychotic symptoms or diagnosis of schizophrenia subsequently in adulthood (Khandaker et al.2014; Metcalf et al.2017), which indicates that reverse causality is an unlikely explanation for the observed association between low-grade inflammation and psychosis. This evidence concerns the gene CRP and schizophrenia.