As one of the characteristic clinical features of the patients with rheumatoid arthritis, the unique character of the patients, somewhat difficult to be persuaded but theoretical, has long been pointed out. The investigators hypothesized that this unique character might be due to the sleep disturbance in the patients possibly due to severe pain of arthritis or unique biochemical disease activities. The investigators test (1) the sleep quality of the patients and draw some characteristic features, and (2) investigated the connection between unique biochemical changes such as the increase of c-fos or wee-1.