Affective instability in complex regional pain syndrome: daily relationships with pain severity and functioning

Abstract

Background: Complex regional pain syndrome (CRPS) is known to involve the most severe pain of all diseases, thus leading to impaired daily functioning. Many patients with CRPS experience emotional problems including affective instability, which may be closely related to the dysfunction of pain control due to the failure of emotional regulation. This study utilized a daily method to examine the role of affective instability in the relationship between daily pain severity and daily functioning (i.e., avoidance, disability, concentration) in patients with CRPS. Method: Ten patients registered with the CRPS Association in Korea, participated in this study. They completed an online end-of-day diary over 15 consecutive days assessing affective instability and daily levels of pain severity, avoidance, disability, and concentration. Data was analyzed using multilevel modelling. Findings: There was significant interaction between negative affect instability and daily pain severity on daily avoidance, daily disability, and daily concentration. The higher the negative affect instability of patients with CRPS, the greater the effect of daily pain severity on daily functioning, whereas the lower the negative affect instability, the less the influence. However, positive affect instability was not associated with all daily functioning variables. Conclusions: Our findings indicated that negative affect instability moderates the relationship between daily pain severity and daily functioning. With increasing negative affective instability, pain is more likely to interfere with daily functioning. Thus, health professionals may need to consider assisting patients in using effective strategies for regulating emotions, particularly negative emotions.