Is psychological distress intrinsic to fibromyalgia syndrome? Cross-sectional analysis in two clinical presentations.

Clinical presentation of fibromyalgia syndrome (FMS) is heterogeneous and often involves psychological comorbidities. Clinical subgrouping of FMS patients has been proposed as a strategy to improve patients' long-term outcomes by helping identify specific treatment needs. Using the 90 Symptom Checklist Revised (SCL-90-R), we have assessed emotional distress in two FMS patient subpopulations discriminated on the basis of their differences in scores on specific items of the Fibromyalgia Impact Questionnaire (FIQ). Subjects classed as type II exhibited high emotional distress on all ten dimensions studied, which included somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, psychoticism, and additional items subscales, as well as on the global severity index (GSI), positive symptom total (PST), and positive symptom distress index (PDSI). T-scores in these patients were above diagnostic cutoff level of 60 on somatization, obsessive-compulsive, and depression subscales. In contrast, the profile exhibited by type I subjects fell entirely within normal values for nonpsychiatric population. Emotional status was significantly inversely correlated with present clinical pain in type I-, but not in type II-fibromyalgia patients. Regression analysis revealed a model based on phobic anxiety, paranoid ideation, and depression subscales as best contributing to classification. The present data suggest that associated psychological distress and maladaptive emotional responses that are commonly attributed to the general FMS population may be largely a distinguishing feature of one subset of patients.