GRM5 and schizophrenia: Some evidence emphasizes an abnormal function of oligomers, consisting of mGluR5, dopamine D2 (D2R) and adenosine A2A receptors (A2AR‐D2R‐mGluR5; Cabello et al., 2009), as well as D2R‐NMDA hetero‐receptor complexes as major contributors to schizophrenia symptoms (Borroto‐Escuela et al., 2017).