(altogether) only around 10,000-15,000 variants appear to explain 90% of the SNP heritability of the investigated major psychiatric disorders and correlated behavioral and cognitive traits. This narrows the search-space for risk variants to around 1% of the 106 quasi-independent SNPs genome-wide and indicates that it is mainly the size and directions of the SNP effects, rather than different SNPs/loci, that influence the development of a specific psychiatric disorder. Furthermore, the considerable overlap suggests that future fine-mapping efforts to pinpoint the causal variants could increase power by combining data from traits with overlapping influencing variants when accounting for the directional effects.
