Beyond Joints: Neuropsychiatric Benefits of TNF-α and IL-6 Inhibitors in Rheumatoid Arthritis—Narrative Review

Rheumatoid arthritis (RA) is a systemic autoimmune disease that, beyond joint destruction, contributes to neuropsychiatric symptoms such as depression, anxiety, and cognitive impairment. These symptoms are often underrecognized despite their major impact on quality of life. Accumulating evidence suggests that pro-inflammatory cytokines, particularly tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), play a key role in this neuroimmune interface. This narrative review examined 16 clinical studies evaluating the effects of biologic therapies targeting TNF-α and IL-6 on mental health outcomes in RA. The total study population comprised 9939 patients, including 2467 treated with TNF-α inhibitors and 7472 with IL-6 or IL-6 receptor inhibitors. TNF-α inhibitors were associated with improved depressive symptoms and emotional well-being. IL-6 inhibitors demonstrated similar psychiatric benefits, particularly in patients with elevated IL-6 levels. The findings highlight that biological therapies in RA may influence not only physical symptoms but also mental health, likely through modulation of neuroimmune pathways including blood–brain barrier permeability, microglial activation, and HPA axis regulation. Future research is needed to clarify these effects in populations stratified by psychiatric comorbidity and inflammatory biomarkers. Clinical implications: Incorporating psychiatric symptom screening and considering neuroinflammatory profiles may help guide the selection of biologic therapy in RA, particularly in patients with comorbid depression or fatigue.