Impact of 5-HTTLPR on SSRI serotonin transporter blockade during emotion regulation: A preliminary fMRI study

Tim Outhred, Pritha Das, Carol Dobson-Stone, Kim L Felmingham, Richard A Bryant, Pradeep J. Nathan, Gin S Malhi, Andrew H Kemp

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17 Citations (Scopus)

Abstract

Background The short ('S') allele of the serotonin transporter (5-HTT)-linked polymorphic region (5-HTTLPR) is associated with increased negative emotion processing bias, and this polymorphism moderates acute effects of selective serotonin reuptake inhibitor (SSRI) treatment. In this preliminary study, we explore the moderating effect of 5-HTTLPR on the impact of the SSRI, escitalopram during emotion regulation of negative emotional stimuli. Method Thirty-six healthy Caucasian, female participants underwent two fMRI scanning sessions following single dose escitalopram and placebo administration separated by a seven-day washout period according to a double-blind, randomized, placebo-controlled crossover design. Functional connectivity analysis was employed with a left (L) amygdala seed and a right interior frontal gyrus (R IFG) target. Results Changes in functional connectivity with emotion regulation and treatment were linearly related to 5-HTTLPR 'L' allele load such that negative R IFG-L amygdala connectivity was increased with an increasing number of 'L' alleles. Therefore, escitalopram may facilitate the effects of reappraisal by enhancing negative functional connectivity, a finding that is greatest in participants homozygous for the 'L' allele and least in those homozygous for the 'S' allele. Limitations Sub-samples of the homozygote 'S/S' and 'L/L' 5-HTTLPR groupings were small. However, the within-subjects nature of the experiment and observing changes at the individual subject level increases our confidence in the findings of the present study. Conclusions The present study elucidates a potential neural mechanism by which antidepressant treatment produces differential treatment outcomes dependent on the 5-HTTLPR polymorphism, providing new and important leads for models of antidepressant action.

Original languageEnglish
Pages (from-to)11-19
Number of pages9
JournalJournal of Affective Disorders
Volume196
DOIs
Publication statusPublished - 15 May 2016

Keywords

  • 5-HTTLPR
  • Antidepressant
  • Emotion
  • fMRI
  • Pharmacogenetics
  • Serotonin

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