Prediction of outcome: Revisiting negative emotions, pain, and functioning

Abstract

Anger, anxiety, and depression are three commonly studied negative emotions in the chronic pain literature. However, the nature of the relationship among these emotions remains somewhat confusing and the results mixed. In this study, linear structural equation modeling was used to examine the associations between the negative emotions (anger, anxiety, and depression) on the one hand, and pain severity and functioning (pain interference and disability) on the other. Contrary to previous findings, the findings indicated that the impact of anger on pain and functioning is mediated by depression. The findings also support but question the commonly held notion that depression and pain have a causative bilateral relationship. Specifically, our findings indicate that depression directly predicts pain severity, but that pain severity does not directly predict depression and other negative emotions. Pain interference, and to a lesser degree, disability appears to mediate the effects of pain severity on depression. The findings also question the previous assertion of a direct relationship between depression and disability. We found that disability predicts depression and anxiety, but depression does not directly predict disability; its effect on disability appears to be mediated by pain interference. Thus, pain interference appears to emerge as a central player mediating the effect of depression (and other negative emotions) on disability, and of pain severity on depression. This finding confirms the result of a previous study (Tan et al., 2002) indicating the central importance of control appraisal over how pain interferes with one's life activities. The implication is that pain interference should be a more central focus of pain management program.