Altered declarative memory in introverted middle-aged adults carrying the BDNF val66met allele

Background: The val66met polymorphism of the brain-derived neurotrophic factor gene (BDNFMet) is associated with impaired learning/memory function, affective dysregulation and maladaptive personality traits. Here, we examine the potential relationship between the BDNFMet allele, introversion and declarative memory in middle-age adults. Methods: A total of 132 middle-aged healthy adults took part in this study that included taking a blood sample for genetic profiling, a short battery of neuropsychological tests and the NEO-Five Factor Inventory (NEO-FFI), widely used to assess the Big Five personality. Results: Controlling for age, level of education and sex, a multiple analysis of covariance (MANCOVA) computing the effect of BDNF polymorphism on extraversion and declarative memory revealed a significant association (D1,128 = 4.79; p = 0.03; ηp2 = 0.053). Using the Sobel Goodman Mediation Test, it was found that 25.61% of the relationship between genotype and declarative memory performance was mediated by introversion. Subsequent correlational analyses yielded a strong and significant correlation (β = 0.53; p < 0.001) between introversion and declarative memory specific to BDNFMet individuals. Conclusion: this study highlights the pertinence of further investigating gene × personality × environment interactions to account for the significant variability that is observed in cognitive function in late life.