The levels of IL-1β in the blood and sigmoid colon mucosa and the proportion of IL-1β-positive cells in the anxiety-depression IBS-D group were significantly higher than those in the non-anxiety-depression IBS-D group, and the levels of IL-10 and the proportion of IL-10-positive cells in the anxiety-depression IBS-D group were significantly lower than those in the non-anxiety-depression IBS-D group (P<0.05). Here, IL1B is linked to major depressive disorder.