1 2 3 5 2 6 7 9 10 11 12 13 14 15 10 16 17 18 18 19 20 2 21 21 23 21 24 25 10 26 27 RA and FM are of course not mutually exclusive. The pathophysiology of each disorder is different, and many patients with RA also have FM, as do many other patients with a variety of chronic rheumatic diseases. The substrate of FM lies in the pain system, which can be functionally activated by distress, a common feature of chronic painful and disabling disorders. How much of the FM mechanism contributes to the low quality of life of RA? Further exploration of the mechanisms causing FM, with its resultant highly significant effect on the quality of life, will have a great impact on the management of not only FM itself but also RA and related musculoskeletal conditions.