Abstract
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.
Highlights
The latest epidemiological world data show an increment of mental illness, together with a parallel increment of health care costs
The purpose of the present study is to examine the possible role of the combined 5-HTTLPR/rs255315-HTT promoter variant and COMT Val158Met, Brain derived Neurotrophic Factor (BDNF) Val66Met gene polymorphisms with specific personality factors that resulted associated to psychological well-being according to literature, to find a genetic mechanism of personality which can guarantee the prevention of mental illnesses associated to personality
Our study demonstrates that COMT, BDNF and 5HTTLPR are associated to specific personality factors, by using personality characteristics to show how much individuals with different gene variants can be discriminated
Summary
The latest epidemiological world data show an increment of mental illness, together with a parallel increment of health care costs. Cloninger’s model, instead, defined four basic personality dimensions: Harm Avoidance, Novelty Seeking, Reward Dependence and Persistence. These dimensions are linked to tendency to feel emotions of fear, anger, love and tenacity, respectively. Some studies showed a positive correlation between Extraversion and the density of the volume of the medial orbitofrontal brain’s area This area is innervated by dopamine fibers, that play an important role in elaborating emotive contents of stimuli [32]. The Behavioral Activation System theory asserts that dopamine is associated to a motivational system, sensible to the reward signals and responsible for escape from punishments [42] According to this neuropsychological theory, an increase of dopamine causes a growth of neural activity, that leads to seek positive and negative reinforcements. Persistence and Cooperativeness allow elevated levels of resilience and emotional intelligence which favors social approval [43,44,45]
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