The relationship between serotonin and personality traits, particularly neuroticism, has been widely studied, yet the influence of serotonin system-related genes on behaviors relevant to negative emotionality has only just begun to be explored. Investigating such genetic influences through endophenotypes and association analyses, the purpose of this study was to analyze personality differences, in self-report and behavior, as a function of genotype. Since high scorers on neuroticism are prone to experience negative emotions and to be emotionally avoidant, these individuals are also known to have increased levels of harm avoidance, which is an evasion from the recognition and awareness of other's emotions. As such, the association between levels of these personality variables and a task measuring the detection of facial expressions of emotion was examined. In particular, we examined levels of neuroticism in relation to serotonin system-related genes and the interactions between serotonin and dopamine system-related genes. In addition, differences in personality variables related to neuroticism were examined as a function of genotype, emotion recognition, and sex. Approximately 200 college students completed self-report measures of personality, including the NEO-Personality Inventory-Revised (NEO-PI-R) and the Temperament and Character Inventory (TCI), and were administered a computerized Affect Recognition Task. Polymerase chain reaction (PCR) was performed on buccal cells, which were also collected from the sample, in order to obtain genotype information. The statistical and genetic results support previous research that connects observable individual differences with an underlying genetic basis.

Supported by Stony Brook University, GCRC grant #5-MO1-RR-10710, and the Simons Foundation.