Mechanisms of behavioral activation, cognitive therapy, and mindfulness meditation for chronic pain: a test of specific vs shared mechanism models in a randomized clinical trial
Melissa A. Day, L. Charles Ward, Jeffrey Borckardt, John Burns, Andrea K. Newman, Dawn M. Ehde, Joy F. Chan, David Reed, Janna L. Friedly, Beverly E. Thorn, M. Elena Mendoza, Sydney A. Drever, Mark P. JensenAbstract
This study tested hypotheses regarding the mechanisms of 3 psychological chronic pain treatments: behavioral activation, cognitive therapy, and mindfulness meditation. The aim was to evaluate the degree to which improvement in the primary outcome (pain interference) was accounted for by preceding changes in cognitive content (pain catastrophizing), cognitive process (mindful nonjudgment), and/or behavior (activity level) during treatment (Primary Aim) and after treatment (Secondary Aim). A total of 302 adults with chronic low back pain were enrolled in a 3-arm parallel randomized clinical trial and completed twice daily ecological momentary assessments of outcome and hypothesized mechanism variables. Participants also wore an activity monitor daily during and after treatment. Slopes were calculated for 4 phases (early treatment, late treatment, early post-treatment, late post-treatment), and analyses of variance were conducted. Structural equation modeling evaluated potential cross-lagged effects. The analyses of variance results showed significant improvement in pain interference, pain catastrophizing, and nonjudgment, but not activity level, with no between treatment differences. The structural equation modeling analyses testing the potential mechanism role of pain catastrophizing and nonjudgment during treatment and after treatment mostly found nonsignificant cross-lagged effects, although changes in outcome and mechanism were significantly correlated at nearly all time periods. Taken together, the strongest support was found for a Shared Mechanisms Model to explain how 3 theoretically unique treatments exert change both during and after treatment. The findings are among the first to delineate the potential mechanisms underlying the variability in post-treatment trajectories of maintenance vs relapse after psychological chronic pain treatment.