Preliminary utility of group acceptance and commitment therapy for patients with intractable chronic pain presenting to a multidisciplinary pain center in Japan: a single-arm pre- and post-comparative study

Background: Multidisciplinary treatments, including psychological approaches such as Acceptance and Commitment Therapy (ACT), are useful for treating chronic pain. However, the few studies investigating the use of ACT on patients with chronic pain in Japan have been limited to case studies and case series. There is a need to develop a Japanese version of a standardized intervention program to expand the use of ACT for patients with chronic pain in Japan. Therefore, the present study examined the preliminary utility of an ACT program for Japanese patients with chronic pain with the ultimate aim of developing a standardized intervention program. Methods: This was a single-arm, pre-test, and post-test comparative study including 23 patients with chronic pain. Patients attended seven weekly group therapy sessions. Psychological scales were administered before and after the intervention, and results were compared using t -tests. Results: Following the intervention, participants displayed more positive attitudes towards pain (Chronic Pain Acceptance and Action Questionnaire-pain willingness, d = 0.83), pain catastrophic thinking (Pain Catastrophizing Scale, d = 0.71), receptive attitudes towards pain (Chronic Pain Acceptance and Action Questionnaire-total, d = 0.60), and the degree of pain interference (Brief Pain Inventory-interference, d = 0.55). The intervention had a moderate effect on pain intensity (Brief Pain Inventory-intensity, d = 0.43) and progress along the value (Valuing Questionnaire, d = 0.67). Conclusions: The preliminary value of the program was demonstrated by its significant effect on pain acceptance. Further efficacy studies comparing groups are required.