This study demonstrates that increasing the number of subjects and SNPs in a meta-analysis is successful in identifying a novel locus for neuroticism. Yet, the effect size of the identified SNP is very small (regression coefficient of −0.04 for the harmonized score with a variance of around 1). Together with our findings of a SNP-based heritability of around 15% and an increase in explained variance in the polygenic risk score analysis when polygenic scores are based on larger sets of SNPs, this suggests that neuroticism is highly polygenic.
