The factors associated with cognitive decline in patients with JIA were average C-reactive protein (OR [95% CI], 1.377 [1.060–1.921]; p = 0.039), depression (OR [95% CI], 3.691 [1.294–10.534]; p = 0.015), and treatment with biologics (OR [95% CI], 0.188 [0.039–0.998]; p = 0.046). This evidence concerns the gene CRP and depressive symptom measurement.