Association between dopamine receptor gene polymorphisms and effects of risperidone treatment: A systematic review and meta-analysis

Background The effect of risperidone treatment in patients with schizophrenia varies according to the dopamine receptor genes. This study aimed to evaluate the relationship between genes of the dopamine receptors (D1, D2, and D3) and the effect of risperidone treatment. Methods Three electronic databases (PubMed, Embase, and Cochrane Library) were searched for relevant cohort or case-control studies published before 9 May 2018. A systematic review and meta-analysis was performed for qualitative and quantitative assessment of the relationship between the dopamine receptors D1, D2, and D3 (DRD1, 2, and 3) and the effect of risperidone treatment. The summary odds ratio (OR) and weighted mean difference (WMD) in a random-effects model were used to measure these relationships. Results Twelve studies involving 24 SNPs were included. DRD2 (Ser311Cys, rs1801028 Ser/Ser) significantly lowered the improvement rate (determined by the PANSS score) unlike Ser/Cys (WMD: -11.58, 95% CI: -17.35 to -5.18). For Asian patients, A241G (rs1799978) AA carriers showed greater improvement after risperidone therapy (P < 0.05). The polymorphisms of 141C Ins/Del (rs1799732), T939C (rs6275), rs6277, and TaqID (rs1800498) may also influence the treatment effect. TaqIA (rs1800497) and TaqIB (rs17294542) were not associated with the rate of response to risperidone. DRD3 was not associated with an improvement in the PANSS total score; however, Ser9Gly might be related to a change in negative symptoms. No significant effect of DRD1 (rs5326, rs4867798, rs4532, and rs11749676) was found. Conclusions Our result supported the hypothesis that DRD2 affected risperidone treatment. DRD1 had no significant effect on the response to risperidone, whereas DRD3 might be associated with an improvement in negative symptoms. Larger observational studies are warranted to verify these findings and identify other genetic factors involved.