Catastrophizing is related to pain modulation in women with fibromyalgia

Previous research has demonstrated that catastrophizing is related to brain responses to pain in patients with fibromyalgia (FM). Little is known about the influence of catastrophizing on pain modulation in this population. This study examined the relationships between pain catastrophizing and cognitive modulation of pain. Twenty women with FM and 20 age-matched female controls (CO) completed the Pain Catastrophizing Scale, the Beck Depression Inventory (BDI), and underwent functional magnetic resonance imaging of moderately painful heat stimuli, administered alone and during distracting cognitive tasks. Perceptual ratings of pain intensity (PI) and pain unpleasantness (PU) were collected after each stimulus. Relationships between pain catastrophizing and brain and perceptual responses to pain were analyzed with linear regression, controlling for scores on the BDI. There were no significant relationships between catastrophizing and brain responses or ratings during pain processing for either FM or CO (p>0.05). For cognitive modulation of pain, significant relationships were found between catastrophizing and both brain responses and ratings for FM and CO. For FM, catastrophizing was significantly related to activity in the bilateral dorsolateral prefrontal cortices (p<0.05). For CO, catastrophizing was significantly related to activity in the contralateral postcentral gyri and superior parietal lobules (p<0.05). For both groups, partial correlations between PI and PU ratings and catastrophizing were significant, ranging between r=0.53-0.79 (p<0.05). This study suggests that catastrophizing interferes with pain modulation in both FM patients and controls. However, the brain systems driving these relationships differed. Controls showed positive relationships with catastrophizing and the BOLD response in regions involved in the sensory and attentional aspects of pain while FM patients showed positive relationships with catastrophizing in regions involved in cognitive aspects of pain. These results suggest that therapies aimed at reducing catastrophizing or improving coping may benefit FM patients by improving pain modulation. Supported by a grant from NIAM/NIH AR50969.