On the other hand, a recent systematic review concluded that the findings from cross-sectional studies regarding the relationship between depression and serum IL-8 levels in nongeriatric populations remained unclear [42], although a study conducted in 2003 found that IL-8 levels significantly and positively correlated with current depressive symptoms in a sample of 53 young men [43]. This evidence concerns the gene CXCL8 and major depressive disorder.