Thus while during IFN-α treatment the scores in the Hamilton Depression-Rating Scale increased significantly in the whole group of drug-free patients and after the end of IFN-α therapy, HAMD-17 total scores in all patients returned to values similar to the baseline measurements before IFN-α treatment (HAMD-17: RM-ANOVA[time]: F[5,134] = 10.45, p<0.001). This evidence concerns the gene IFNA1 and major depressive disorder.