Details regarding genotyping using a GWAS array are available in supplemental text. SNPs (MAF > .05; call rate > 95%) within six endocannabinoid-related genes (CNR1, FAAH, MGLL, DAGLA, DAGLB, and NAPEPLD), ±10kbps to include both promoter and flanker regions, were extracted into a gene set using PLINK (v1.07; http://pngu.mgh.harvard.edu/purcell/plink/; Purcell et al., 2007). CNR2 was not included in our analysis due to lack of coverage on the array. The resulting 79 SNPs were then pruned for independence (50-SNP window shifted 5 SNPs at each step, linkage disequilibrium r2 threshold = .80), which resulted in a pruned set of 65 independent SNPs (excluding CNR2), ranging from 3 (NAPEPLD) to 24 (MGLL) within each gene (Table S2).
