IL6 and attention deficit-hyperactivity disorder: The most recent review, including ten studies with 1046 patients and 3333 controls, suggested a modest increase of Interleukin (IL)-6 in patients with ADHD [19], but reported no change for the majority of proteins (i.e., C-reactive Protein (CRP), IL1-β, IL-10, INF-γ), and even found lower levels for Tumor necrosis factor (TNF)-α.