Stressful events and information processing dispositions moderate the relationship between positive and negative affect: implications for pain patients.

Relationships between positive affect, negative affect, and pain were analyzed as a prospective function of stressful events in a sample of rheumatoid arthritis patients and as a cross-sectional function of an information processing disposition in persons with fibromyalgia. Positive affect and negative affect were statistically separate factors overall in both samples. In addition, negative affect and pain were related across all conditions. However, positive affect and negative affect were more negatively correlated during stressful periods and more negatively correlated for patients who processed information in a more simplistic fashion. Also, positive affect predicted pain during stressful times and did so for patients who processed information more simplistically as well. These data suggest positive affect and negative affect are unique factors whose interrelation and external correlates are not static.