A retrospective observational study comparing somatosensory amplification in fibromyalgia, chronic pain, psychiatric disorders and healthy subjects.

Abstract

Somatosensory amplification (SA) has been described as an important feature of somatoform disorders, and an "amplifying somatic style" has been reported as a negative connotation of body perception. As widespread pain (WSP) in fibromyalgia (FM) is due to a central sensitization (CS) rather than organic alterations, there has been discussion as to whether FM is equivalent to or distinct from somatization disorder (SD). Assuming SD and FM are two distinct entities, an increase in somatic amplification should be expected only in subjects who have SD, regardless of the type of pain they experience. Purpose of the study was to explore the magnitude of SA in FM, and whether this depends on the association with SD. FM (n=159) other forms of chronic pain (OCP, n=582), psychiatric (Psy, n=53) and healthy (H, n=55) subjects were investigated using the Somatosensory Amplification Scale (SSAS), Illness Behavior Questionnaire, (IBQ), Italian Pain Questionnaire (IPQ), and Cold Pressor Test (CPT) in a retrospective observational study. FM subjects displayed higher SSAS scores than the other groups. High SSAS score was associated with FM (OR=8.39; 95%CI: 5.43-12.46) but not OCP. Although FM has the highest prevalence of SD (x2=14.07; p=.007), high SSAS scores were associated with SD in OCP but not in FM. Unlike in OCP, in FM high SSAS scores were independent of the presence of SD. From a biopsychosocial perspective, SSAS may be a factor associated with the onset of FM.