The rg between cannabis use and cannabis use disorder was 0·50 (SE 0·05, p=1·50 × 10−21). Of the eight genome-wide significant SNPs associated with cannabis use, only four had p<0·05 in the meta-analysis of cannabis use disorder (modest sample overlap between the two studies: genetic covariance intercept 0·014 [SE 0·005]).5 Conditioning the summary statistics of cannabis use disorder for loci associated with cannabis use neither substantially modified the effect sizes of the genome-wide significant loci (rs4732724, β=–0·11, SE 0·02, p=8·25 × 10−9; rs7783012, β=0·10, SE 0·02, p=2·62 × 10−9) nor identified additional novel loci (appendix p 18). The heritability of cannabis use disorder adjusted for cannabis use loci (using mtCOJO35) was 0·095 (SE 0·01) on the liability scale (estimated population prevalence 8·5%).
