The Relationship between the Therapeutic Response to Antipsychotic Drugs and the Dopamine D2, D3, and D4 Receptor Gene Polymorphisms in Korean Schizophrenic Patients

ABSTRACT

OBJECTIVES: A considerable number of pharmacogenetic studies have been performed in recent years to define the association of antipsychotic drug response with dopamine receptor polymorphisms. The purpose of this study was to investigate the relationship between the therapeutic response to anti-psychotic drugs and the polymorphisms of the dopamine D2, D3, and D4 receptor genes(DRD2, DRD3 and DRD4, respectively). METHODS: We conducted retrospective chart review of 200 consecutively hospitalized patients with the diagnosis of schizophrenia(DSM-IV) who were treated with various antipsychotics(94% atypical antipsychotics) at Bugok National Hospital, Korea. The patients were divided into two groups, responders and non-responders, by responsiveness to antipsychotic drugs according to a four-point scale used in previous studies; responders included moderate to marked responded patients and non-responders included none to minimal responded patients. We analyzed the Ser311Cys polymorphism in the DRD2, the Ser9Gly polymorphism in the DRD3, and the exon III 48 bp repeat polymorphism in the DRD4. RESULTS: Among the total patients of 200, 141(70.5%) were categorized as responders. There were no significant differences in the frequencies of the DRD2, DRD3, and DRD4 alleles and genotypes between responders and non-responders. CONCLUSION: These results suggest that the Ser311Cys polymorphism in the DRD2, the Ser9Gly polymorphism in the DRD3, and the exon III 48bp repeat polymorphism in the DRD4 are not associated with the therapeutic response to antipsychotic drugs in Korean schizophrenic patients. A larger prospective study is needed to elucidate the association between antipsychotic response and dopamine receptor gene polymorphism.