Altered Episodic Memory in Introverted Young Adults Carrying the BDNF(Met) Allele

While most studies have been interested in the distinct, predisposing roles of the common BDNF Val66Met variant and extraversion personality traits on episodic memory, very few studies have looked at the synergistic effects of genetic and personality factors to account for cognitive variance. This is surprising considering recent reports challenging the long-held belief that the BDNF(Met) variant negatively impacts cognitive function. A total of 75 young healthy adults (26 of them carried at least one copy of the BDNF(Met) allele) took part in this study consisting of genetic profiling from saliva, personality assessment using the Revised NEO Personality Inventory (NEO PI-R) and a short battery of neuropsychological tests. An ANOVA revealed that BDNF(Met) carriers were significantly less extraverted than BDNF(Val) carriers (F(1,73) = 9.54; p < 0.01; η(p)(2) = 0.126). Moreover, extraversion was found to significantly moderate the relationship between the BDNF genotype and episodic memory performance (p = 0.03). Subsequent correlational analyses yielded a strong and significant correlation (r = 0.542; p < 0.005) between introversion and delayed episodic memory specific to BDNF(Met) individuals. The present study suggests that introversion and the BDNF(Met) variant synergistically interact to reduce episodic memory performance in healthy, young adults. These findings reaffirm that a more accurate explanation of cognitive variance can be achieved by looking at the synergistic effects of genotype and phenotype factors.