S100B and attention deficit-hyperactivity disorder: The association of hyperactive-impulsive ratings in the ADHD group with IL-16 (r +0.66, p = 0.015) was confirmed by the regression (R2 0.52, F(2,18) = 9.82, p = 0.001: β +0.80, p = 0.000) with modest support from decreasing levels of S100B (β -0.42, p = 0.035).