Genotype for cannabis dependence and control subjects was determined using an ABI 7900HT available at the Mount Sinai Quantitative PCR Shared Resource Facility. DRD2 SNPs: TaqIA (rs1800497) is located ∼10 kb downstream of the DRD2 and affects striatal DRD2 receptor density [27], rs6277 and rs1076560 are associated with DRD2 expression and cognitive/attentional performance [28]. PENK SNPs: rs2576573, rs2609997 and rs6474063 were chosen based on pairwise linkage disequilibrium (LD) relationships (r2) of an r2 threshold of 0.8 and on haplotype data (www.hapmap.org) showing a minimum allele frequency of 0.10 in the population. The call rate was 100% and all genotypes examined conformed to Hardy-Weinberg equilibrium.
