CRP and major depressive disorder: As shown in Figure 5, The most common keywords in the field of IL-6 signaling pathway in mendelian randomization are “mendelian randomization,” “interleukin-6,” “il-6,” “c-reactive protein,” “association,” “coronary-heart-disease,” “inflammation,” “instruments,” “risk,” “rheumatoid arthritis,” “depression.” Cluster analysis of the keywords also revealed that mendelian randomization involving IL-6 signaling pathway was mostly related to cardiovascular diseases.