Vowles, K. E., & McCracken, L. M. (2008). Acceptance and values-based action in chronic pain: A study of treatment effectiveness and process. Journal of Consulting and Clinical Psychology, 76, 397-407.
Developing approaches within CBT are increasingly process-oriented and based on a functional and contextual framework that differs from the focus of earlier work. The present study investigated the effectiveness of Acceptance and Commitment Therapy (Hayes, Strosahl, and Wilson, 1999) in the treatment of chronic pain and also examined two processes from this model, acceptance and values-based action. Participants included 171 completers of an interdisciplinary treatment program, 66.7% of whom completed a 3-month follow-up assessment as well. Results indicated significant improvements for pain, depression, pain-related anxiety, disability, medical visits, work status, and physical performance. Effect size statistics were uniformly medium or larger. According to reliable change analyses, 75.4% of patients demonstrated improvement in at least one key domain. Both acceptance of pain and values-based action improved, and increases in these processes were associated with improvements in the primary outcome domains.