Fibromyalgia and rheumatoid arthritis: personality and psychopathology differences from the Minnesota Multiphasic Personality Inventory-2

The fibromyalgia syndrome (FM) is a chronic widespread pain condition whose etiology remains unknown. Within a psychosocial approach to FM, personality may play a role as predisposing and/or maintaining factor. A meta-analytic study has identified a distinct Minnesota Multiphasic Personality Inventory-2 (MMPI-2) clinical profile between FM female patients and healthy controls, but the differences between FM and other chronic pain conditions with clear etiology are not established. This cross-sectional study compares the clinical MMPI-2 profile in FM and rheumatoid arthritis (RA) patients, identifies typical groups of each pathology, and further characterizes these groups in the broad MMPI-2 personality and psychopathology dimensions. The MMPI-2 scales were assessed in a sample of 70 women (FM: n = 38, Mage = 46.03, SDage = 8.48; RA: n = 32, Mage = 45.31, SDage = 8.68). The FM group had clinically significant elevations on five clinical scales (Hypochondriasis, Depression, Hysteria, Psychasthenia and Schizophrenia), while RA group had none. A K-Means cluster analysis allowed the identification of a typical profile of each pathology, and subsequent MANCOVAs identified important features of FM patients on several MMPI-2 dimensions. We conclude there is specificity in the personality and psychopathology characteristics of FM patients