The analysis of large samples indicates that CRP is a strong predictor of depression, emphasising the central role of systemic inflammation in the pathogenesis of depression.67,68,83 Other studies have shown that high plasma CRP levels and increased TNF and soluble IL-6 receptors in the CSF are associated with severe depressive symptoms such as anhedonia and reduced motivation.52,53,60,68,83. This evidence concerns the gene TNF and major depressive disorder.