Taken together, these findings suggest that depression may be characterized by elevated pro-inflammatory signaling via leptin concentrations through alternate inflammatory pathways distinct to CRP, which relates to blunted mid-insula signals previously evident in MDD patients during the processing of bodily sensations57,58 as well as reduced insula and putamen responses during reward anticipation in girls at high risk for MDD59. Here, LEP is linked to major depressive disorder.