IFNA1 and depressive symptom measurement: Major depressive disorder is a highly recurrent illness, and prior episodes were significant predictors of a recurrence.1 The risk of the recurrence of major depressive disorder progressively increased with each successive episode.39 A history of major depressive disorder was also a significant predictive factor of IFN-α-induced depression.10 In the matched cohort, IFN-α-induced depression patients with a depressive history might have had a higher risk of recurrence, but the difference did not reach a statistical significance.