GRM2 and schizophrenia: Importantly, these data agree with postmortem studies that were prospectively designed to compare mGluR expression in PFC between schizophrenia patients and healthy controls, but incidentally observed that expression of both mGluR2/3 and mGluR5 are negatively correlated with age (Crook et al., 2002; Corti et al., 2011; Frank et al., 2011).