Association of COMT, BDNF and 5-HTT functional polymorphisms with personality characteristics

Background: The real impact of genetic factors on personality is still unknown, even if in literature about 50% of variance in personality traits are considered genetically determined. The determination of the genetic variance in personality traits could promote psychological well-being and the prevention of psychopathologies, because there are many experimental evidences showing that mental illness is associated to personality. Numerous studies have showed that Catechol-O-methyltransferase (COMT), brain derived neurotrophic factor (BDNF) and serotonin transporter (5-HTT) are genes whose variants are associated with personality traits. This aim of this study is the investigation of the association between personality traits and 5-HTTLPR/rs255315-HTT promoter variant, COMT Val158Met and BDNF Val66Met gene polymorphisms. Methods: The sample was composed by 132 healthy female students. Genomic DNA was extracted from buccal swab, while personality was assessed with Cloninger's Temperament and Character Inventory-Revised (TCI-R). Linear discriminant analysis was used to analyze how personality characteristics can differentiate individuals in relation to their genetic polymorphisms. Results: Data showed that the temperament trait Reward Dependence discriminated individuals with different BDNF variants; Novelty Seeking and Harm Avoidance discriminated individuals with different 5HTTLPR variants; Persistence discriminated individuals with different COMT variants. Conclusions: Since these traits are connected to psychological diseases as depression, social anxiety, anorexia and obsessive-compulsive disorders of personality, the study of their genetic component can be used as intermediary issue to better define the connection between genes and predisposition toward maladaptive behavior and mental illness.