IFNA1 and depressive symptom measurement: Consequently, the SNP rs1863918 located on chromosome 5 showed a strong association with IFN-induced depression in the combined results of the GWAS and replication stage in the allele frequency model (odds ratio = 2.55, 95% confidence interval = 1.80–3.61, P = 7.89×10−8) (Table 2).