The Val66Met Coding Variant of the Brain-Derived Neurotrophic Factor (BDNF) Gene Does Not Contribute Toward Variation in the Personality Trait Neuroticism

Background The val66met variant located within the brain-derived neurotrophic factor gene (BDNF) has previously been associated with human neuroticism, a dimension of personality strongly predictive of depressive illness. Methods Here we report an attempt to replicate this association using three populations of extreme neuroticism scorers derived from two large English cohorts (n = 88,142 and n = 20,921). On the basis of the current literature, which indicates that an effect of BDNF may only become apparent in those individuals exposed to stress, a gene-environment interaction was also sought. Results No statistically significant effects were identified, although simulations indicated that the samples held sufficient power to detect a main effect accounting for just .75% of variation and an interaction accounting for 4% of variation. Conclusions These data do not support the hypothesis that the val66met BDNF polymorphism contributes toward variation in the human personality trait neuroticism, at least as indexed by the Eysenck Personality Questionnaire.