Due to their increased association with longevity, conscientiousness and neuroticism were especially hypothesised to associate with longevity candidate genes, but neither of these traits showed strong evidence of association with any of the genes. Most notable were the SNPs in SYNJ2 that showed p-values lower than .05 for NEO neuroticism (five SNPs) and IPIP emotional stability (six SNPs). SNPs in this same gene were also associated with agreeableness and depression scores, although they too did not exceed the corrected probability threshold. There is biological evidence to suggest SYNJ2 may have a plausible role in disordered mood. Decreased expression of SYNJ2 has been shown in the temporal cortex of major depressive disorder patients [33] and in a rodent model of depression overlap between cingulate cortex gene expression, stress behaviour and anti-depressant response identified SYNJ2 as a candidate gene for therapeutic targets [34]. While this is aligned with our findings of association with depression and neuroticism, our strongest support for SYNJ2 was with agreeableness, where rs350292 showed association in our replication sample of more than 17 000 participants and the direction of
