Outhred, T and Das, P and Dobson-Stone, C and Felmingham, KL and Bryant, RA and Nathan, PJ and Malhi, GS and Kemp, AH, Impact of 5-HTTLPR on SSRI serotonin transporter blockade during emotion regulation: A preliminary fMRI study, Journal of affective disorders, 196 pp. 11-19. ISSN 0165-0327 (2016) [Refereed Article]
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.
|Item Type:||Refereed Article|
|Keywords:||5-HTTLPR; Antidepressant; Emotion; Pharmacogenetics; Serotonin; fMRI|
|Research Division:||Medical and Health Sciences|
|Research Group:||Public Health and Health Services|
|Research Field:||Mental Health|
|Objective Group:||Public Health (excl. Specific Population Health)|
|Objective Field:||Mental Health|
|Author:||Felmingham, KL (Professor Kim Felmingham)|
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