A research conducted on 218 rheumatoid arthritis (RA) patients by Japanese research team from Nagoya City University and Nagoya University Graduate Schools of Medicine indicated that depression had a direct impact on the severity of the pain. The research, in which levels of CRP (a plasma protein produced by the liver) were measured, indicated that the levels also rose during incidents of acute inflammation in RA. The combined effects of high CRP levels and depression predicted severe pain even more strongly. The result may help clinicians to control pain by addressing their patients’ psychological symptoms.