Objective: Variations in the gene for dopamine D2 receptor (DRD2) might have an influence on the outcome of antipsychotic treatment in schizophrenia. The objective of this study was to investigate the influence of DRD2 polymorphisms on treatment outcomes in patients with schizophrenia.
Methods: The sample composed of 156 Malaysian outpatients with stable schizophrenia on maintenance antipsychotic treatment at a psychiatric clinic. Psychopathology was evaluated using the Positive and Negative Symptoms Scale. DNA was extracted from blood and subjected to DRD2 PCR-genotyping.
Results: Patients with Cys311 allele had more pronounced or severe symptoms of schizophrenia than those without this allele. The former group had a significantly worse treatment response and presented with more prominent negative symptoms. Although there was no significant association between Positive and Negative Symptoms Scale scores and the Pro310Ser, -141C Ins/Del, A-241G or TaqI A polymorphisms, patients with the wild-type -141C Ins allele tended to have less pronounced or milder symptoms of schizophrenia compared with patients with the variant -141C Del allele.
Conclusion: The results suggest that DRD2 polymorphisms may have implications for the symptoms of schizophrenia and a predictor for treatment outcomes in a subgroup of patients with schizophrenia in Malaysia. However, further investigation with a larger sample is required to confirm these findings.