XAF1 and major depressive disorder: For the red module, the hub genes are the interferon genes IFIT3, IFI35 and XAF1, PARP14 and two probes for UBE2L6. Of these, PARP14 is highly inversely correlated to MDD and adult ADHD, as are MX1 and EIF2AK2. In addition, two probes for STAT1 show high gene significance for MDD and OAS2 for adult ADHD.