DRD2 and schizophrenia: Similarly, a landmark genome-wide association study identifying over 100 loci associated with schizophrenia found significant hits implicating the dopamine D2 receptor gene indicating its possible role in the etiology of the disease (Flint & Munafo, 2014; Ripke et al., 2014; Ripke, Walters, & O'Donovan, 2020).