Perception of emotion in facial stimuli: The interaction of ADRA2A and COMT genotypes, and sex.

Emotional facial stimuli are important social signals that are essential to be perceived and recognized in order to make appropriate decisions and responses in everyday communication. The ability to voluntarily guide attention to perceive and recognize emotions, and react to them varies largely across individuals, and has a strong genetic component (Friedman et al., 2008). Two key genetic variants of the catecholamine system that have been related to emotion perception and attention are the catechol-O-methyl transferase genetic variant (COMT Val158Met) and the α2A-receptor gene promoter polymorphism (ADRA2A C-1291G) accordingly. So far, the interaction of the two with sex in emotion perception has not been studied. Multilevel modeling method was applied to study how COMT Val158Met, ADRA2A C-1291G and sex are associated with measures of emotion perception in a large sample of young adults. Participants (n=506) completed emotion recognition and behavioral emotion detection tasks. It was found that COMT Val158Met genotype in combination with the ADRA2A C-1291G and sex predicts emotion detection, and perception of valence and arousal. In simple visual detection, the ADRA2A C-1291G G-allele leads to slower detection of a highly arousing face (scheming), which is modulated by each additional COMT Val158Met Met-allele and male sex predicting faster responses. The combination of G-allele, Met-allele and male sex also predicts higher perceived negativity in sad faces. No effects of C-1291G, Val158Met, and sex were found on verbal emotion recognition. Applying the findings to study the interplay between catecholamine-O-methyl transferase activity and α2A-receptors in emotion perception disorders (such as ADHD, autism and schizophrenia) in men and women would be the next step towards understanding individual differences in emotion perception.