Pooling pharmacogenetic studies on the serotonin transporter: a mega-analysis.

Pharmacogenetic studies on antidepressants have reported an association between the promoter of the serotonin transporter gene (SERTPR) and response to antidepressant treatment. In the present study, individual subject data from three pharmacogenetic studies on SERTPR were pooled ('mega-analysis') to investigate the role of this gene in the antidepressant activity of selective serotonin reuptake inhibitors (SSRIs). A group of 548 patients who were treated with different SSRIs in a double blind design were included; the severity of depressive symptoms was weekly assessed with the Hamilton Rating Scale for Depression. SERPR allelic variants were determined in each subject using a PCR-based technique. In the whole sample, subjects with SERPR() l/l variants showed a significantly better response to treatment, and this effect was independent from analyzed demographic and clinical variables but was not uniform across samples. This result supports the involvement of the SERTPR gene in response to antidepressant treatments.