%0 Journal Article %T Pain Mystery Score Beliefs: A Comparison of Fibromyalgia and Rheumatoid Arthritis %A Robert Ferrari %A Anthony Science Russell %J International Journal of Rheumatology %D 2014 %I Hindawi Publishing Corporation %R 10.1155/2014/593507 %X Objectives. To compare the mysteriousness scores of the Pain Beliefs and Perceptions Inventory in fibromyalgia. Methods. Two cohorts of patients, one with fibromyalgia (FM) and one with rheumatoid arthritis (RA), completed the Mystery Scale component of the Pain Beliefs and Perceptions Inventory to determine whether subjects in the two diagnostic groups had significantly different scores on the Mystery Scale. Results. A total of 126 subjects (64 FM, 62 RA) completed all questionnaires. The FM group had a greater percentage of female subjects, more severe pain, more severe anxiety, more severe depression, and a higher perceived injustice score. When the RA and FM group scores for the Mystery Scale were adjusted for age, sex, pain severity, HADS scores, and perceived injustice scores, the FM group still had a higher Mystery Scale score. Discussion. Fibromyalgia is associated with a higher level of perception of mysteriousness in the Pain Beliefs and Perceptions Inventory than is seen with rheumatoid arthritis. This difference appears to be independent of levels of pain, depression, anxiety, and perceived injustice. This sense of mysteriousness may reflect a lack of understanding of pain in fibromyalgia as previously reported and may be an area to be addressed in therapy. 1. Introduction It has previously been shown that fibromyalgia patients differ from other widespread pain patients in that fibromyalgia patients are more likely to perceive a much greater degree of difficulty both in understanding the cause of their pain and in explaining the cause of their pain to others [1]. This was concluded after utilization of the Understand Pain Scale and the Explain Pain Scale. That is, subjects were asked to indicate on a Likert scale the degree to which they ¡°understand the cause of their pain (the reason they have pain)¡± (the Understand Pain Scale) and the degree to which they ¡°can explain the cause of their pain (the reason they have pain) to others¡± (the Explain Pain Scale). Using these scales and controlling for age, gender, and duration of pain, fibromyalgia subjects had higher scores than comparator groups, which included whiplash-associated disorder, tendinitis/bursitis, and osteoarthritis. Although a handful of rheumatoid arthritis subjects were included in this study [1], they were few, and to date there is no further validation of the Understand Pain Scale and Explain Pain Scale, in patients with painful disorders. On the other hand, the Pain Beliefs and Perceptions Inventory has had a much more detailed study of its construct [2, 3]. Specific items of %U http://www.hindawi.com/journals/ijr/2014/593507/