Psychological Fibromyalgianess Exists on a Continuous Spectrum

Objective: To determine if key psychological factors associated with the fibromyalgia (FM) phenotype, herein termed psychological fibromyalgianess, exist on a spectrum with asymptomatic persons at one end and those with FM at the other. Methods: Ninety-eight women with FM, diagnosed according to ACR 1990 criteria, and 35 female healthy controls without pain were studied. Applied questionnaires included the following: Big 5 personality scale, Perceived Stress scale, Fibromyalgia Impact Questionnaire, Perceived control of internal states, Mastery scale, Optimism scale and the profile of mood states scale. Results: Normality plots showed key psychological variables of FM subjects and HCs to be in the same population. These variables showed a gradient effect with lower levels in controls and higher levels in FM subjects, all associating with the FM phenotypic features of sleep and cognitive change and fatigue (p<0.001), with pain showing a ceiling effect. Both the psychological factors and the FM-related symptoms were of a much lesser degree in controls compared to patients with FM. Conclusions: Selected key psychological factors in females that associate with the FM clinical phenotype are also present in healthy controls and exist on a spectrum, with lower levels seen in asymptomatic non-FM women and higher levels seen in those with FM. Variation in the extent of certain psychological factors (psychological fibromyalgianess) links to clinical features of FM, consistent with these factors being key contributors to FM.