The relationship of mood state to the severity of clinical pain.

The present study was designed to identify the relationship among severity of pain, negative moods and positive moods. Seventy pain patients were interviewed 24 h preceding and 24 h following a myelography procedure. Patient data, containing pain and mood measures, were subjected to a confirmatory factor analysis. Three simple-structured factors emerged and were labeled Pain Severity, Negative Mood and Positive Mood. The Pain Severity factor was positively correlated with the Negative Mood factor but was unrelated to the Positive Mood factor. Similarly, the Negative Mood factor was independent of the Positive Mood factor. Three additional analyses were performed in order to examine the robustness of the initial factor solution. One analysis was performed on an enlarged sample, utilizing additional data from 49 chronic pain patients, and the other two were executed on data from the post-myelography interview. The factor structure and factor interrelationships were replicated in all three analyses. The implications of the observed factor correlations and the possible utility of the Pain Severity factor as a reliable pain measure are discussed.