We performed a conditional-and-joint analysis (GCTA-COJO)14 to identify independent signals within significant OCD loci. This approach performs a conditional and joint analysis on the basis of conditional P-values before calculating the joint effects of all selected SNPs. We used the stepwise model selection procedure to select independently associated SNPs. The linkage disequilibrium reference sample was created from 73,005 individuals from the QIMR Berghofer Medical Research Institute genetic epidemiology cohort. The distance assumed for complete linkage disequilibrium was 10 Mb, and we used the default P-value threshold of 5 × 10−8 to define a genome-wide significant hit.
