Indices of inflammation [e.g., circulating levels of cytokines (e.g., interleukin-6 (IL-6) and acute phase proteins (e.g., C-reactive protein (CRP)] are elevated in individuals with depression compared to controls12 and inflammatory biomarkers have been linked to specific aspects of depression, such as anhedonia and negative affect13, 14. This evidence concerns the gene IL6 and major depressive disorder.