By contrast, in both samples and in a meta-analysis inclusive of published data (n=15251), we found no evidence for a main effect of BDNF Val66Met on neuroticism.
Altered hippocampal volume, the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism, and neuroticism have each been implicated in the etiology of psychiatric disorders, especially depression.
Recently, it was shown that the Val allele of the BDNF Val66Met substitution polymorphism showed a significant association with higher mean neuroticism scores of the NEO-Five Factor Inventory (NEO-FFI) in healthy subjects, and previous studies suggested the Val allele to be increased in bipolar disorder families.
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.