DRD2 and schizophrenia: The dopamine hypothesis, the current leading theory of the pathogenesis of schizophrenia [4,5], is supported by genetic studies indicating that single nucleotide variations (SNVs) related to dopaminergic transmission, such as DRD2 [6], COMT [7], DISC1 [8], and PCLO [9,10,11], are associated with a higher risk of schizophrenia [5,12].