No association of serotonin transporter polymorphism (5-HTTVNTR and 5-HTTLPR) with characteristics and treatment response to atypical antipsychotic agents in schizophrenic patients

Background: Serotonin transporter is a candidate gene for the pathogenesis of some psychiatric disorders. The aim of this study was to examine the role of the serotonin transporter gene polymorphism in the clinical aspects of schizophrenia including symptomatology and therapeutic response. Methods: This study comprised 141 unrelated patients who strictly met the DSM-IV criteria for schizophrenia and 115 control subjects. All subjects were of Korean ethnicity. Serotonin transporter intron 2 VNTR polymorphism (5-HTTVNTR) and serotonin transporter linked polymorphic region polymorphism (5-HTTLPR) were analyzed in schizophrenia patients and control subjects. The Positive and Negative Symptom Scale (PANSS) was used at baseline and 6 weeks after atypical antipsychotic treatment to evaluate the clinical symptoms. Body mass index (BMI), the Barnes Akathisia Rating Scale (BARS), the Simpson-Angus Rating Scale (EPS) for adverse effect and the Calgary Depression rating Scale for Schizophrenia (CDSS) were measured. Results: There were no significant differences in the frequency of genotypes between schizophrenia patients and control subjects. There were no significant differences in PANSS scores before treatment according to the serotonin transporter genotypes. Treatment response after atypical antipsychotics did not differ among the genotypes. No difference was shown among the genotypes for the scales in adverse effects and depression (BMI, BARS, EPS, CDSS). Conclusions: Our results suggest that the serotonin transporter polymorphism does not seem to be a susceptibility factor for schizophrenia. Similarly, the serotonin transporter polymorphism might not affect the therapeutic response and adverse effect to atypical antipsychotics in Korean patients with schizophrenia. Further studies with a larger number of subjects are required to better understand the role of the serotonin transporter polymorphism in schizophrenia.