Acceptance and Commitment Therapy for chronic pain on functioning: A systematic review of randomized controlled trials

•We explored the efficacy of ACT on functioning for chronic pain.•Twelve randomized controlled trials were retrieved.•Low to moderate evidence indicates an immediate effect of ACT on functioning.•It is uncertain whether the effect can be sustained. Chronic pain is a worldwide health problem, Acceptance and Commitment Therapy (ACT) is regarded as one of the promising interventions. ACT aims to help chronic pain patients to create space for pursuing valued life activities in spite of pain. This systematic review of randomized controlled trials (RCTs) examined the efficacy of ACT on functioning for chronic pain. Literature search was performed among seven databases, and 12 RCTs were retrieved. The revised Cochrane risk of bias tool (RoB 2.0) was employed to assess the quality of the 12 RCTs, of which 10 were rated as “low risks”, and 2 as “some concerns”. Effect sizes of single RCTs and the pooled effect sizes of meta analyses were all rated by Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Low to moderate evidence showed that ACT played a positive immediate role in functioning for patients with chronic pain; however, it is inconsistent whether the effect can be sustained. More RCTs are warranted within specific chronic pain conditions.