The mutual influence between RA and emotional disorders may be due to their common pathogenesis, mainly including proinflammatory mechanisms such as TNF-α; interferon-α, IL-1β, IL-6, and IL-17; oxidative stress factors, and neurotransmitter changes at the CNS and blood–brain barrier (BBB) cell levels (25, 167). This evidence concerns the gene IL17A and rheumatoid arthritis.