Demographics of the participants.

This study investigated the relationship between psychological traits and chronic pain using the Structured Association Technique (SAT) method to evaluate psychological factors associated with chronic pain. The participants included 105 older adults (23 men, 82 women, mean age 80.82 years) who received rehabilitation services. Chronic pain severity was assessed using a numerical rating scale (NRS), and psychological traits were evaluated by SAT. In addition, maternal attachment experiences in childhood were examined. The NRS showed significant positive correlations with the self-suppressing behavioral pattern (S) scale (r = 0.31, p = 0.001), and the depression (D) scale (r = 0.31, p = 0.001). The proportion of participants with high scores on both the S and D scales (SD group) was notably higher in the high NRS group. Logistic regression analysis showed that the SD group had a higher odds ratio (OR = 8.469, p = 0.004) for severe chronic pain, suggesting that SD traits independently contribute to worse pain. In the SD group, the self-denial scale scores were high, and self-denial traits showed a negative correlation with maternal attachment experiences in childhood. This finding indicates that poor maternal attachment may enhance self-denial traits, which in turn indirectly worsen pain through their effects on S and D traits. The results of this study highlight the importance of S and D traits as psychological factors in chronic pain, particularly in Japanese populations, and suggest that assessing self-suppressing behavioral patterns may be beneficial for pain management. However, the cross-cultural validity of the SAT scales requires further investigation. SAT therapy may provide a comprehensive approach to the treatment and prevention of complex conditions influenced by psychological and social factors, including chronic pain.