In order to test for a potential impact of the risk locus on age at first diagnosis, a case only study was performed testing for association of the index variant (rs56372821) and variants in LD with this (r2 > 0.7; 19 variants) with age at first diagnosis. Date of diagnosis was identified from register information in the Danish Psychiatric Central Research Register52. Analysis for association with age at first diagnosis (natural logarithm (age at first diagnosis)) was done using linear regression and the same covariates as used in the GWAS (PCs, wave and the psychiatric disorders). A dominant model with respect to the risk allele, was applied.
