Effectiveness of Acceptance and Commitment Therapy for Chronic Non-Malignant Pain: a Randomized Controlled Trial

Chronic non‐malignant pain (CNMP) is associated with significant psychological distress,functional impairment, and reduced quality of life, and pharmacological treatment aloneoften provides limited relief. This study uses a three‐arm, single‐blind randomizedcontrolled trial with a pretest‐posttest parallel‐group design to compare Acceptance andCommitment Therapy (ACT) against Cognitive Behavioral Therapy (CBT, active comparator)and Treatment as Usual (TAU, control).Sixty adults (aged 18‐60) with a physician‐confirmed diagnosis of chronic non‐malignantmusculoskeletal or widespread pain (duration ≥3 months) were enrolled using purposivesampling and randomly allocated to ACT, CBT, or TAU (n=20 per group) using manual simplerandomization (fishbowl method). Eligible participants scored ≥4 on the Numerical RatingScale (pain intensity), ≥4 on the Brief Pain Inventory interference subscale, and ≥20 onthe Pain Catastrophizing Scale, and were willing/able to attend all sessions. Individualswith severe psychiatric disorders, severe cognitive/neurological impairment, concurrentstructured psychological treatment for pain, or unstable medical conditions wereexcluded.The ACT intervention, delivered over 10 weekly sessions using a manual‐based protocoladapted for chronic pain, targets the six core processes of the psychological flexibilitymodel: acceptance, cognitive defusion, present‐moment awareness, self‐as‐context, valuesclarification, and committed action. The CBT intervention, also delivered over 10 weeklysessions, targets maladaptive pain‐related cognitions and behaviors through cognitiverestructuring, behavioral activation, activity pacing, relaxation training,problem‐solving, and coping skills. The TAU group continues routinemedical/pharmacological care without structured psychological intervention.Outcome assessors are blinded to group allocation; participants and therapists could notbe blinded given the nature of the interventions. Outcomes are assessed at baseline andpost‐intervention using the Numerical Rating Scale (pain intensity), Chronic PainAcceptance Questionnaire (pain acceptance), Brief Pain Inventory (pain interference),Acceptance and Action Questionnaire‐II (psychological flexibility), Pain CatastrophizingScale, Hospital Anxiety and Depression Scale, and WHOQOL‐BREF (quality of life). Datacollection is complete for the majority of participants; a small number of participantsare currently in their final follow‐up sessions before post‐intervention assessment.The study aims to (1) evaluate within‐group change in ACT and CBT from pretest toposttest across all outcomes; (2) compare ACT versus CBT on post‐intervention outcomes,with primary focus on pain acceptance, psychological flexibility, and pain interference;(3) examine whether change in psychological flexibility predicts change in paininterference and catastrophizing across both treatment groups; (4) compare ACT and CBT onanxiety, depression, and quality of life; and (5) compare ACT and CBT against TAU on alloutcome measures. Findings are expected to clarify the comparative efficacy and mechanismof action of ACT relative to an established active treatment, contributing evidence fornon‐pharmacological, mechanism‐informed pain management, particularly within anunder‐studied Pakistani population.