Acceptance and values-based action in chronic pain: a three-year follow-up analysis of treatment effectiveness and process.

Recent developments in CBT emphasize the promotion of psychological flexibility to improve daily functioning for people with a wide range of health conditions. In particular, one of these approaches, Acceptance and Commitment Therapy (ACT), has been studied for treatment of chronic pain. While trials have provided good support for treatment effectiveness through follow-ups of as long as seven months, the longer-term impact is not known. The present study of 108 participants with chronic pain examined outcomes three years after treatment completion and included analyses of two key treatment processes, acceptance of pain and values-based action. Overall, results indicated significant improvements in emotional and physical functioning relative to the start of treatment, as well as good maintenance of treatment gains relative to an earlier follow-up assessment. Effect size statistics were generally medium or large. At the three-year follow-up, 64.8% of patients had reliably improved in at least one key domain. Improvements in acceptance of pain and values-based action were associated with improvements in outcome measures. A "treatment responder" analysis, using variables collected at pre-treatment and shorter term follow-up, failed to identify any salient predictors of response. This study adds to the growing literature supporting the effectiveness of ACT for chronic pain and yields evidence for both statistical and clinical significance of improvements over a three-year period.