GRM5 and schizophrenia: In this connection, it has been shown that a mGluR5 agonist effectively reverses the (pro‐psychotic) behavioral effects of ketamine (Chan, Chiu, Sou, & Chen, 2008), indicating, once again, that mGluR5 plays an important role in the regulation of NMDA‐mediated neurotransmission in schizophrenia‐related processes.