ACTing with Mindfulness for Pain (AMP): A pilot randomized controlled trial of an integrated acceptance and...

Acceptance and commitment therapy (ACT) is an empirically-supported psychotherapy for chronic pain. Although mindfulness is a key component of ACT, most ACT protocols do not include formal mindfulness meditation practice as a principal treatment method, leaving open the question of whether formal practice may bolster ACT's effects. Addressing this gap, the present study assessed the feasibility and preliminary treatment effects of ACTing with Mindfulness for Pain (AMP), an ACT-based protocol that emphasizes and measures daily formal mindfulness meditation practice. A total of 87 Veterans (M_age = 49.44, SD = 12.42) were randomized to AMP or cognitive behavioral therapy (CBT). Feasibility was supported by attainment of enrollment targets, achievement of retention rates at post-treatment greater than 80 %, and high levels of treatment credibility and satisfaction. Treatment expectancy was lower than hypothesized in both groups. Within the AMP group, there were significant improvements in pain interference (primary outcome; d = -0.58), pain acceptance (d = 0.72), cognitive defusion (d = 0.23) and pain catastrophizing (d = -0.50) at posttreatment. Within the CBT group, there were significant improvements in pain interference (d = -0.59), pain acceptance (d = 0.50), and pain catastrophizing (d = -0.39) at posttreatment. In both groups, effect sizes were reduced at 3-month follow-up. Home meditation practice was dose-dependently associated with a greater reduction of depressive symptoms and pain-related helplessness in the AMP group. Taken together, despite meeting important feasibility metrics, the effect size estimates from this pilot randomized controlled trial highlight the need for further treatment development before moving to formal efficacy evaluation.