Pathway analysis for SSD gene signatures showed that differential expressed genes enriched in 47 pathways, and most pathways were involved in regulation of DNA replication, IL2 signaling events mediated by STAT5, and Wnt signaling pathway, etc. For MDD gene signatures, the results of pathway analysis suggested that differential expressed genes enriched in 53 pathways, 2 of which also were identified in SSD, including MAPK signaling pathway and Wnt signaling pathway. The gene discussed is IL2; the disease is major depressive disorder.