Object: Numerous relevant variants of dopamine receptors have been identified in schizophrenia. The Ser9Gly gene polymorphism of dopamine D3 receptor is known as a susceptibility factor for the disease. In addition, it has a role in the modification of therapeutic effect of antipsychotics. In this naturalistic study the authors investigated the relationship between this polymorphism and the therapeutic response to atypical antipsychotics.
Method: 75 patients with schizophrenia according to DSM-IV and 45 healthy controls were recruited. The patients were divided to responder and nonresponder subgroups, cut-off: > 20 point improvement in Global Assessment of Functioning. By polymerase chain reaction the genotype of dopamine D3 receptor of every participant was determined.
Results: The Ser9Ser genotype of dopamine D3 receptor was more frequent in the nonresponder subgroup (64%, p = 0.0018). The Ser9 allele was overrepresented among nonresponder patients (82%, p = 0.0172).
Conclusion: Based on our results, the worse therapeutic response to atypical antipsychotics is associated with Ser9 variant of dopamine D3 receptor.