Finally, DRD2 has also been investigated for association with methamphetamine dependence and methamphetamine-induced psychosis. Šerý et al. (2001) found no association between polymorphisms in DRD2 and methamphetamine dependence. Ujike et al. (2009) tested 3 SNPs in DRD2: 141C insertion/deletion (rs1799732; -/C), Ser311Cys (rs1801028; C/G) and Taq1A, and found that the Taq1A A2 (C) allele, which was associated with good response to bupropion for smoking cessation, was associated with prolonged methamphetamine psychosis (A2/A2, A1/A2 genotypes). Additionally, they found that the Del/Del and Ins/Del genotypes of 141C insertion allele (rs1799732) were associated with rapid onset of psychotic symptoms (within 3 years of initial abuse). Therefore, the Taq1A polymorphism, along with other polymorphisms in DRD2, may influence development of stimulant-induced psychosis as well as drug dependence.
