RA patients with anxiety (p = 0.003), receiving biologics (including etanercept, adalimumab, golimumab, abatacept, tocilizumab, tofacitinib, and rituximab) (p = 0.01), retired (p = 0.006), and had a disease duration of more than 5 years showed significantly lower serum level of BDNF. This evidence concerns the gene BDNF and rheumatoid arthritis.