GRM2 and psychotic disorder: In addition, post-mortem studies in the cortex of untreated schizophrenia patients found higher expression of 5-HT2A and lower expression of mGluR2, which might reflect a predisposing pattern to psychosis, indicating that the 5-HT2A/mGluR2 complex might be involved in the altered cortical processes of schizophrenia resulting in a promising unconventional target for the treatment of psychosis [86].