GWAS meta-analysis of life-time cannabis use including 184,765 individuals, wich identified eight genome-wide significant independent risk loci14. Four GWASs of problematic use or diagnosed CUD have been conducted; two without genome-wide significant findings15,16 and two recent reporting genome-wide significant associations, albeit with negative or ambiguous replication results: a study of DSM-IV cannabis dependence criterion counts in a combined sample of 14,754 European Americans and African Americans17, which reported three genome-wide significant loci associated with cannabis use severity; and a GWAS of cannabis dependence of 2,080 European cases and 6,435 controls which identified one genome-wide significant locus18.
