Two earlier OCD GWAS meta-analyses, both containing a subset of the data included in this analysis12,13, showed SNP-based heritabilities of 8.5% (assuming a 3% population prevalence) and 16% (assuming a 2% population prevalence). The first GWAS (ncases = 14,140, ncontrols = 562,117)12 found one genome-wide significant locus associated with OCD, while the second (ncases = 37,015, ncontrols = 948,616)13 identified 15 independent genome-wide significant loci. As with other complex traits, increased sample sizes are needed for a more comprehensive understanding of the underlying genetic etiology of OCD and its genetic relationships with related disorders.
