Symptoms, the nature of fibromyalgia, and diagnostic and statistical manual 5 (DSM-5) defined mental illness in patients with rheumatoid arthritis and fibromyalgia. PLoS One 2014;9:e88740

Purpose: To describe and evaluate somatic symptoms in patients with rheumatoid arthritis (RA) and fibromyalgia, determine the relation between somatization syndromes and fibromyalgia, and evaluate symptom data in light of the Diagnostic and Statistical Manual-5 (DSM-5) criteria for somatic symptom disorder. Methods: We administered the Patient Health Questionnaire-15 (PHQ-15), a measure of somatic symptom severity to 6,233 persons with fibromyalgia, RA, and osteoarthritis. PHQ-15 scores of 5, 10, and 15 represent low, medium, and high somatic symptom severity cut-points. A likely somatization syndrome was diagnosed when PHQ-15 score was $10. The intensity of fibromyalgia diagnostic symptoms was measured by the polysymptomatic distress (PSD) scale. Results: 26.4 % of RA patients and 88.9 % with fibromyalgia had PHQ-15 scores $10 compared with 9.3 % in the genera