title: Personality, dopamine receptor D4 exon III polymorphisms, and academic achievement in medical students.
abstract: This study investigated the relationships between genetic polymorphisms, personality traits, and academic achievement in medical school students. Study subjects were 220 1st-year medical students at Korea University Medical School during two consecutive academic years (2003-2004). Grade-point averages (GPA) during the second semester of the 1st year of the medical school were obtained as a measure of academic achievement. In addition, all participants completed the Temperament and Character Inventory and questionnaires on depression and anxiety. The polymorphisms in exon III of the dopamine D4 receptor (DRD4) were determined using the polymerase chain reaction. Our results revealed that both male and female subjects with a higher GPA may be characterized as having higher persistence and lower novelty seeking traits. In addition, male subjects with high GPA had higher scores in self directedness and female subjects with a higher GPA may be characterized as having higher scores in harm avoidance. Male students with 4-repeat alleles had a significantly lower GPA than male students without 4-repeat alleles. This relationship also remained after controlling for the personality variables, none of which showed a relationship with the polymorphism after Bonferroni correction. For females, however, no associations could be found between GPA and the polymorphism. Thus, the present study demonstrated for the first time a possible influence of the DRD4 48 bp variable number of tandem repeats polymorphism on academic achievement and proved that this was not mediated by performance-associated personality traits.
authors.affiliation: Department of Neuropsychiatry, Hangang Sacred Heart Hospital, Hallym University Medical Center, Seoul, South Korea.
authors.forename: Byung-Joo
authors.initials: BJ
authors.lastname: Ham
authors.forename: Young-Mee
authors.initials: YM
authors.lastname: Lee
authors.forename: Meyoung-Kon
authors.initials: MK
authors.lastname: Kim
authors.forename: Juneyoung
authors.initials: J
authors.lastname: Lee
authors.forename: Duck-Sun
authors.initials: DS
authors.lastname: Ahn
authors.forename: Myoung-Jin
authors.initials: MJ
authors.lastname: Choi
authors.forename: In Kyoon
authors.initials: IK
authors.lastname: Lyoo
authors.forename: Ihn-Geun
authors.initials: IG
authors.lastname: Choi
authors.forename: Min-Soo
authors.initials: MS
authors.lastname: Lee
mesh_terms: D000328:Adult; D016009:Chi-Square Distribution; D004522:Educational Status; D005091:Exons; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D018598:Minisatellite Repeats / Q000235:genetics*; D010551:Personality / Q000235:genetics*; D010555:Personality Inventory; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D050638:Receptors, Dopamine D4 / Q000235:genetics*; D012044:Regression Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012737:Sex Factors; D013337:Students, Medical
chemical_list: C493599:DRD4 protein, human; D012333:RNA, Messenger; D050638:Receptors, Dopamine D4