Acceptance and commitment therapy for chronic pain: evidence of mediation and clinically significant change following an abbreviated interdisciplinary program of rehabilitation.

UNLABELLED: There is an emerging body of evidence regarding interdisciplinary acceptance and commitment therapy in the rehabilitative treatment of chronic pain. This study evaluated the reliability and clinical significance of change following an open trial that was briefer than that examined in previous work. In addition, the possible mediating effect of psychological flexibility, which is theorized to underlie the acceptance and commitment therapy model, was examined. Participants included 117 completers of an interdisciplinary program of rehabilitation for chronic pain. Assessment took place at treatment onset and conclusion, and at a 3-month follow-up when 78 patients (66.7%) provided data. At the 3-month follow-up, 46.2% of patients achieved clinically significant change, and 58.9% achieved reliable change, in at least 1 key measure of functioning (depression, pain anxiety, and disability). Changes in measures of psychological flexibility significantly mediated changes in disability, depression, pain-related anxiety, number of medical visits, and the number of classes of prescribed analgesics. These results add to the growing body of evidence supporting interdisciplinary acceptance and commitment therapy for chronic pain, particularly with regard to the clinical significance of an abbreviated course of treatment. Further, improvements appear to be mediated by changes in the processes specified within the theoretical model. PERSPECTIVE: Outcomes of an abbreviated interdisciplinary treatment for chronic pain based on a particular theoretical model are presented. Analyses indicated that improvements at follow-up mediated change in the theorized treatment process. Clinically significant change was indicated in just under half of participants. These data may be helpful to clinicians and researchers interested in intervention approaches and mechanisms of change.