RGS2 and psychiatric disorder: Koning et al. [76] studied the association of thirteen SNPs of nine candidate genes (DRD2, DRD3, 5HTR2A, 5HTR2C, COMT, NQO1, GSTP1, RGS2, and MnSOD) with the risk of developing AIA in 402 Northern European patients with mental disorders taking APs for at least a month.