A polymorphism of the gene SLC6A4, encoding the serotonin (5HT) transporter (SERT), has been linked to the etiology of anxiety-related traits in humans (Mazzanti et al., 1998; Forstner et al., 2017) and SLC6A4 knockout mice exhibit an anxious-like phenotype (Uher and McGuffin, 2008). This evidence concerns the gene SLC6A4 and Anxiety.