Personality Subgroups in the Fibromyalgia Syndrome

It has become increasingly clear that there are subgroups of fibromyalgia syndrome [FMS] patients (1–4). These can differ with respect to comorbidities (5), with respect to genetic predisposition (6–9), with respect to response to treatment modalities (10–13), and now we learn from our lead article that the same applies to personality traits as well. The lead article for this issue of the Journal of Musculoskeletal Pain [JMP] comes from Linköping, Sweden but involves three other sites in Sweden (14). Their objectives were to determine whether there are temperament and character differences between FMS and healthy normal controls [HNC], and whether these measures will identify subgroups of FMS patients. The current study (15) was conducted with 191 ambulatory female FMS outpatients using the Swedish version of the Temperament and Character Inventory [TCI] (15). One of the authors had conducted a previous study (16) that addressed the first question using the same instrument and 38 FMS patients matched to HNC, but she concluded that the study needed repetition with a larger sample size. The authors considered the temperament variables to represent heritable traits that program automatic perceptions or responses, while the character traits were considered to be self-concepts acquired through a variety of environmental exposures. The reader is encouraged to review the authors’ descriptions of these concepts because they represent a new vocabulary that must be understood to put the findings of the study into context. With respect to the authors’ objective questions, the results of the study say “yes” and “yes” but then what does that mean? The authors offer explanations, insights, and limitations. Now, following a logical sequence, we must wonder whether the contrast of FMS with HNC will be similar when compared with a disease control group also suffering from chronic pain, or even just a chronic illness. There is data available from other studies with this instrument comparing pain patients with HNC (17–19), so it may be possible to answer this question without enrolling new patients. The authors tangentially address this issue in their discussion, but to do it right would require sharing of data between the different studies. It will also be instructive to see analyses from administration of this questionnaire instrument to FMS patients and controls from other ethnic groups, to explore familial patterning, and to see stratification of the subgroups on the basis of symptom severity with respect to a variety of clinical domains including pain, insomnia, depression, anxiety, age, and dyscognition. From São Paulo, Brazil (20) comes a report of a case-controlled study exploring the role of tobacco smoking in FMS. One can’t help suspecting that smoking is a factor when seeing a habituated patient with so much pain, insomnia, and distress. The authors’ findings may come as a surprise. From Granada, Spain comes a report (21) regarding pressure-pain thresholds in patients with FMS, rheumatoid arthritis [RA], and systemic lupus erythematosus [SLE] compared with HNC. The authors used an electronic dolorimeter and averaged two measurements at each of 24 body sites in each session. Test-retest