IL6 and major depressive disorder: In a study by Basterzi et al. (2005), the level of IL-6 did not differ between depressed and healthy subjects; however, after 6 weeks of treatment with SSRI, there was a statistically significant decrease in the level of IL-6 in the group of patients [62], and when the symptoms of depression decreased during treatment, a decrease in the level of IL-6 is observed [63].