In addition to the canonical G protein-dependent cAMP-PKA signalling pathway, the D2R signalling is also mediated by the Akt-GSK3β via β-arrestin2; many studies have indicated that Akt-GSK3β signalling plays a critical role in the pathophysiology of schizophrenia [24, 25, 27, 64]. This evidence concerns the gene DRD2 and schizophrenia.