GRM2 and schizophrenia: These studies provided foundational research which motivated multiple drug discovery programs to develop selective mGlu2 PAMs [151–155] that have efficacy in animal models of schizophrenia including TASP0443294 [156], JNJ-40411813/ADX71149 [157, 158], AZD8529 [159], and SAR218645 [160] (Table 2).