Examining the Dynamic Relationship between Positive and Negative Emotions as a Function of Pain, Fatigue, and Stress in Individuals with and without Fibromyalgia

Abstract

Affective disruptions, particularly deficits in positive affect, are characteristic of fibromyalgia (FM). The Dynamic Model of Affect (DMA), which posits that the inverse association between positive and negative emotions becomes stronger during episodes of high stress and pain, may help to explain this vulnerability. Evidence for the DMA has been found in individuals with FM, but our understanding of which types of stressors and emotional dimensions contribute to these affective dynamics is limited. In this study, we tested the assumptions of the DMA by examining whether pain, stress, and fatigue moderate the momentary association between positive and negative emotions and whether this moderating effect is different for individuals with versus without FM. One-hundred adults (n=50 with FM; n=50 without FM) completed ecological momentary assessments for pain, stress, fatigue, negative emotions (depression, anger, anxiety), and positive emotion (vigor) 5X/day for seven days using a smartphone application. Multilevel random effects modeling indicated that there was a stronger inverse association between vigor and depression during times of greater pain, stress, and fatigue. Similarly, there was a stronger inverse association between vigor and anger when stress and fatigue were high. For both depression and anger, these relationships were stronger in the FM group than the non-FM group. There were no differences in the anxiety-vigor association as a function of pain, stress, or fatigue. These findings are consistent with the DMA and suggest that individuals with FM show a pattern of stronger inverse associations between positive and negative emotions during times of pain, stress, and/or fatigue; however, this appears to be specific to only some types of negative emotions – anger and depression, but not anxiety. Findings also indicate that fluctuations in fatigue may be as or more important than fluctuations in pain in the emotional dynamics of individuals with FM. Grant support from NIH/NIAMS award #K01AR064275.