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Influence of DRD2 polymorphisms on the clinical outcomes of patients with schizophrenia

Zahari, Zalinaa,c; Teh, Lay Kekd; Ismail, Ruslia; Razali, Salleh Mohdb

doi: 10.1097/YPG.0b013e3283437250
Original Articles

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.

aPharmacogenetics Research Group, Institute for Research in Molecular Medicine

bDepartment of Psychiatry, USM, Health Campus

cDepartment of Pharmacy, Hospital USM, Kelantan

dFaculty of Pharmacy, Universiti Teknologi Mara, Selangor, Malaysia

Correspondence to Salleh Mohd Razali, MD, Department of Psychiatry, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kelantan, Malaysia Tel: +609 7673000; fax: +609 7653370; e-mail:

Received November 7, 2009

Accepted November 23, 2010

© 2011 Lippincott Williams & Wilkins, Inc.