In order to investigate whether depressive disorder was a major confounding factor for gene expression regulation, we calculated the Spearman’s correlation coefficients separately in depressed and non-depressed subjects. All the 1,554 SNP-probe pairs identified as eQTL in the present study achieved high correlations for both depressed and non-depressed subjects (average Spearman’s correlation of the 3 sample groups >0.4, FDR-corrected P<0.01 in non-depressed subjects and >0.5, FDR-corrected P<0.005 in depressed subjects for all 1,554 SNP-probe pairs).
