MMP9 and impulse control disorder: We observed protease-inhibitor pairs such as MMP-9 (Spearman ρ = 0.71, p = 0.0006) and S100A12 (Spearman ρ = 0.73, p = 0.0003), which can inactivate MMP-9, as correlated with disease severity in both CCD and ICD.