Negative effect of anger on chronic pain intensity is modified by multiple mood states other than anger: A large population-based cross-sectional study in Japan

Objectives: To investigate whether mood states other than anger can modify the association between anger and pain intensity in individuals with chronic pain. Methods: We analysed 22,059 participants with chronic pain, including 214 participants with rheumatoid arthritis (RA), who completed a questionnaire. The Profile of Mood States short form (POMS-SF) was used to assess six dimensions of mood states (anger-hostility, tension-anxiety, depression-dejection, confusion, fatigue, and vigour). A numerical rating scale (NRS) assessed pain intensity. We examined the association between anger-hostility and the NRS and the relationship between POMS-SF components. Moderation analyses were used to investigate whether the five mood states other than anger-hostility modified the effect of anger-hostility on the NRS. Results: Anger-hostility contributed to pain intensity. Although increased mood states other than vigour were associated with increased pain intensity, these increased mood states appeared to suppress the effect of anger-hostility on pain intensity. Increased vigour was associated with decreased pain intensity and increased the effect of anger-hostility on pain intensity. Conclusions: Mood states other than anger may influence the association between anger and pain intensity in individuals with chronic pain. It is important to focus on complicated mood states and anger in individuals with chronic pain, including RA.