DPP4 and major depressive disorder: The effects of GLP-1RAs in persons with depression were reported in several observational cohort studies conducted by Gamble et al.31, Wium-Anderson et al.32, Battini et al.33, and Tagliapietra et al.34 Gamble et al.31 observed a decrease in incident depression or self-harm in persons who had previously been prescribed dipeptidyl peptidase-4 inhibitors (DPP-4i), sulfonylureas, and DPP-4i, GLP-1RAs, or GLP-1RAs and sulfonylureas.