High serum levels of IFN-γ, alongside IL-6, have previously been reported to predict a poor response to antipsychotic medication after 12 weeks of treatment in patients with first episode psychosis (Mondelli et al., 2015), but we did not observe significant differences in the relationship between IFN-γ and brain glutamate between treatment responders and treatment non-responders in the current study. This evidence concerns the gene IFNG and psychotic disorder.