There have not been many GWAS of illicit-drug-use disorders. A study using 708 DSM-IV cannabis-dependent cases and 2,346 cannabis-exposed nondependent controls from the Study of Addiction: Genetics and Environment data set showed a suggestive association between cannabis dependence and variants in the ANKFN1 gene on human chromosome 17 (4). In a sample of 325 methadone-stabilized, formerly severe heroin addicts and 250 control individuals, Nielsen et al. (100) used a pooled GWAS approach to find variants associated with vulnerability to heroin addiction.
