DRD2 and psychotic disorder: Dorsal striatal dopamine dysfunction underlies the symptoms of psychosis (McCutcheon, Beck, Jauhar, & Howes, 2018), and the efficacy of antipsychotics is related to their antagonistic effects at the dopamine D2 receptor (Miyamoto, Miyake, Jarskog, Fleischhacker, & Lieberman, 2012).