BackgroundThere have been conflicting reports on whether the length polymorphism in
the promoter of the serotonin transporter gene (5-HTTLPR) moderates the
antidepressant effects of selective serotonin reuptake inhibitors
(SSRIs). We hypothesised that the pharmacogenetic effect of 5-HTTLPR is
modulated by gender, age and other variants in the serotonin transporter
gene.AimsTo test the hypothesis that the 5-HTTLPR differently influences response
to escitalopram (an SSRI) compared with nortriptyline (a noradrenaline
reuptake inhibitor).MethodThe 5-HTTLPR and 13 additional markers across the serotonin transporter
gene were genotyped in 795 adults with moderate-to-severe depression
treated with escitalopram or nortriptyline in the Genome Based
Therapeutic Drugs for Depression (GENDEP) project.ResultsThe 5-HTTLPR moderated the response to escitalopram, with long-allele
carriers improving more than short-allele homozygotes. A significant
three-way interaction between 5-HTTLPR, drug and gender indicated that
the effect was concentrated in males treated with escitalopram. The
single-nucleotide polymorphism rs2020933 also influenced outcome.ConclusionsThe effect of 5-HTTLPR on antidepressant response is SSRI specific
conditional on gender and modulated by another polymorphism at the 5' end
of the serotonin transporter gene.
Moderation of antidepressant response by the serotonin
transporter gene