Serotonin transporter gene polymorphism and treatment response to serotonin reuptake inhibitor (escitalopram) in depression: An open pilot study

BACKGROUND: Blocking of the serotonin transporter is the main mechanism of action of SSRIs; therefore, the gene encoding this protein is a strong candidate for a possible genetic influence on the treatment response. AIM: To evaluate relationship between serotonin transporter gene promoter region polymorphism and the efficacy of SSRI (escitalopram) treatment in depression. MATERIALS AND METHODS: Fifty-seven consecutive patients with unipolar depressive episode (DSM IV criteria) were genotyped for the SERT gene polymorphism and treated with escitalopram 20 mg/day. Weekly assessment (HAM-D-21) was made for treatment response up to 6 weeks. RESULTS: Significant (P > 0.0001) difference between groups (ll vs. ss or ls) in response to treatment by escitalopram was revealed by our study. However, no difference with respect to age, gender, or onset of illness was observed between genotype subgroups. CONCLUSION: The study suggests that serotonin transporter gene polymorphism may have an influence on the effectiveness of SSRI treatment in depressive disorders, irrespective of clinical variables. Further controlled studies are required to validate these results