Cannabis use and cannabis use disorder were modestly genetically correlated (rg 0·50) but conditioning for cannabis use loci did not substantially reduce the heritability of cannabis use disorder, and although it reduced the significance of the top loci, the effect sizes remained consistent. Although this does not fully account for possible index-event bias,59 it suggests that the findings are not due to cannabis exposure alone. Cannabis use and cannabis use disorder also show divergent genetic relationships with educational attainment,47 BMI,50 and age at birth of first child, with cannabis use disorder indexing greater impairment in these psychosocial and anthropometric indices than cannabis use. This divergence is similar to that found between alcohol intake and alcohol use disorder.7, 8
