Experimental Assessment of Affective Processing in Fibromyalgia

Fibromyalgia syndrome (FMS) is a chronic pain disorder associated with widespread musculoskeletal pain, tenderness, and fatigue. Additionally, correlational research suggests negative affect (eg, depression, anxiety) and deficits in positive affect may contribute to FMS symptomatology. However, well-controlled, experimental research is necessary to ascertain whether patients with FMS have problems in affective processing. The present study used a well-validated picture-viewing paradigm to evoke emotional responses in 17 patients with FMS and 17 sex- and age-matched healthy control participants. Each participant viewed pleasant (erotica), neutral, and unpleasant (attack related) pictures, and abrupt white noises were delivered during two-thirds of the pictures to evoke startle eyeblinks. Appetitive and defensive responding was assessed from subjective (valence/pleasure and arousal ratings) and physiological (corrugator EMG, heart rate, skin-conductance response, startle-reflex modulation) reactions to pictures. Results suggested FMS was associated with greater defensive activation (displeasure, subjective arousal, corrugator EMG) to the unpleasant, threat-related pictures, but not deficits in appetitive activation to erotic pictures. Although preliminary, these data suggest individuals with FMS have deficits in affective processing, but this dysregulation may be limited to defensive activation. Implications for treatment and future research are discussed. Perspective: Fibromyalgia is a debilitating disease associated with affective distress. Results from the present study suggest that FMS is associated with enhanced defensive activation to nonpainful threat-related stimuli, but not deficits in appetitive reactions to erotic stimuli. These findings have implications for the treatment and study of FMS. (C) 2009 by the American Pain Society