Laboratory participants were genotyped for rs3800373 with a 2μl TaqMan allelic discrimination assay (Applied Biosystems, Foster City, CA, USA). This SNP tags a previously studied common FKBP5 haplotype.11-14, 37 Laboratory subjects were assigned to EA or AA subject groups based on a previously described genetic marker method26, 38 or based on self-report. Rs3800373 was directly genotyped for subjects with DSM-IV-based withdrawal symptoms by either the HumanOmni1-Quad v1.0 or the Infinium® HumanCore Exome BeadChip (Illumina, San Diego, CA, USA). One subject was retained from each pair determined to be related (identity-by-descent>0.25), and subjects with sex-mismatches where excluded. The overall genotype-missing rate was <2%. The array-genotyped subjects were clustered as EA or AA based on the first two principal components, and subjects with clustering that was discordant from their self-reported race were excluded.
