Variations in the promoter region of the serotonin transporter gene and biased attention for emotional information: a meta-analysis

Background: Selective attention to negative information has been strongly implicated in the etiology and maintenance of anxiety and offered as a potential intermediate phenotype for anxiety disorders. Attention biases have been studied in relation to a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) offering equivocal findings. The present meta-analysis tested whether the extant published data support the notion that variation in the 5-HTTLPR genotype modulates selective attention to negative information.

Methods: Eleven relevant samples from 10 published articles were identified through a systematic literature search (total n = 807). Relevant attention bias and 5-HTTLPR data were extracted based on specific coding rules, and Cohen's d effect size index was used to calculate all outcome measures. Publication bias was assessed using various methods.

Results: Carriers of the low (SS, SL(G), L(G)L(G)) transmission efficacy genotype display attentional vigilance toward negatively valenced stimuli, a pattern not found in the intermediate (SL(A), L(A)L(G)) and high (L(A)L(A)) efficacy genotypes. This phenomenon emerges as of medium effect size.

Conclusions: The meta-analysis supports the notion that allele variants of the 5-HTTLPR are associated with selective attention to negative stimuli. More studies are needed to fully establish the consistency of this effect. Future studies applying systematic attention bias modification may shed further light on the role of 5-HTTLPR in the development of anxiety disorders and in the prediction of clinical response to attention bias modification treatments.