Association of serotonin transporter gene polymorphism and emotion regulation.

Metacognitive strategies of emotion regulation such as an objective perspective of one's self are known as primary factors in mindfulness intervention. Earlier studies, however, suggest that the effect of mindfulness differs because of the individual variability. In this study, we investigated the influence of the serotonin transporter gene polymorphism during the application of a metacognitive strategy of emotion regulation. Short (S) homozygotes showed more negative emotional states than SL individuals in both metacognition and control conditions. The high frequency of heart rate variability, however, increased in the metacognition condition only in S homozygotes. This result indicated that the metacognitive strategy of emotion regulation is more effective for increasing parasympathetic dominance in S homozygotes than in SL individuals.