GRM5 and Cognitive impairment: mGluR5 PAMs, such as CDPPB and more recently VU0364289, demonstrated the ability to attenuate phencyclidine and amphetamine-induced hyperlocomotion, social interaction deficits, prepulse inhibition deficits and importantly, cognitive deficits (which are largely untreated by current antipsychotics) [1,44].