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Bottom line
Acceptance and commitment therapy appears to help adults with chronic pain across functional and psychological outcomes, with the largest and most consistent effects on functional impairment, pain acceptance, and psychological flexibility; effects on pain intensity and quality of life are smaller, and longer-term durability beyond three months remains uncertain.
Moderate evidencePublished
Evidence hierarchy
Study participants
Adults aged 16 and older with chronic non-cancer pain lasting more than three months (including three fibromyalgia trials); mostly from Europe, majority female.
Study Summary
This systematic review and meta-analysis pooled 21 randomized controlled trials (1,298 participants) comparing acceptance and commitment therapy (ACT) against treatment-as-usual or waiting-list controls in adults with chronic non-cancer pain. At post-treatment, ACT showed a significant medium effect on pain interference, functional impairment, pain acceptance, psychological inflexibility, and depression, and a small effect on pain intensity, anxiety, and quality of life. Benefits were maintained at three months post-treatment, where functional impairment showed a large effect and the other measured outcomes showed medium effects. The authors conclude ACT may be an effective intervention for chronic pain but note clinical heterogeneity, English-only inclusion, and lack of preregistration as limitations, calling for studies in specific pain conditions with longer follow-up.
Key Findings
| Finding | Detail | Impact |
|---|---|---|
| ACT improved pain interference and functional impairment at post-treatment | Pain interference showed a medium effect (SMD -0.50, 95% CI -0.66 to -0.34; 625 participants) and functional impairment a moderate-to-large effect (SMD -0.74, 95% CI -1.13 to -0.35; 638 participants), both P<0.001, favoring ACT over control. | High |
| Psychological outcomes and pain acceptance improved at post-treatment | Pain acceptance SMD 0.68 (95% CI 0.50 to 0.87; 1,008 participants), psychological inflexibility SMD -0.65 (95% CI -0.89 to -0.40; 548), depression SMD -0.59 (95% CI -0.82 to -0.35; 983), anxiety SMD -0.47 (95% CI -0.69 to -0.24; 751), all P<0.001. | High |
| Pain intensity and quality of life showed smaller effects at post-treatment | Pain intensity SMD -0.37 (95% CI -0.57 to -0.17; 1,114 participants) and QOL SMD 0.43 (95% CI 0.12 to 0.74; 294 participants), both favoring ACT. | Medium |
| Benefits were maintained at three months post-treatment | At three months, functional impairment showed a large effect (SMD -0.85, 95% CI -1.32 to -0.39; 421 participants) and the other outcomes showed medium effects, e.g., pain acceptance SMD 0.75, depression SMD -0.67, pain intensity SMD -0.57, anxiety SMD -0.53 (P=0.008). QOL was not analyzed at follow-up. | High |
| Included trials were generally of good methodological quality with low publication-bias risk | Yates scores ranged 6 to 8; the funnel plot for pain interference was roughly symmetric, suggesting low publication-bias risk; sensitivity analyses (random vs fixed effects, leave-one-out) showed stable results. However, some studies had unclear or high risk for allocation concealment and attrition bias. | Medium |
Pain interference showed a medium effect (SMD -0.50, 95% CI -0.66 to -0.34; 625 participants) and functional impairment a moderate-to-large effect (SMD -0.74, 95% CI -1.13 to -0.35; 638 participants), both P<0.001, favoring ACT over control.
Pain acceptance SMD 0.68 (95% CI 0.50 to 0.87; 1,008 participants), psychological inflexibility SMD -0.65 (95% CI -0.89 to -0.40; 548), depression SMD -0.59 (95% CI -0.82 to -0.35; 983), anxiety SMD -0.47 (95% CI -0.69 to -0.24; 751), all P<0.001.
Pain intensity SMD -0.37 (95% CI -0.57 to -0.17; 1,114 participants) and QOL SMD 0.43 (95% CI 0.12 to 0.74; 294 participants), both favoring ACT.
At three months, functional impairment showed a large effect (SMD -0.85, 95% CI -1.32 to -0.39; 421 participants) and the other outcomes showed medium effects, e.g., pain acceptance SMD 0.75, depression SMD -0.67, pain intensity SMD -0.57, anxiety SMD -0.53 (P=0.008). QOL was not analyzed at follow-up.
Yates scores ranged 6 to 8; the funnel plot for pain interference was roughly symmetric, suggesting low publication-bias risk; sensitivity analyses (random vs fixed effects, leave-one-out) showed stable results. However, some studies had unclear or high risk for allocation concealment and attrition bias.
Strengths
- Pooled 21 RCTs (1,298 participants), roughly doubling the trial count of the earlier benchmark review by Hughes et al. (11 RCTs), increasing statistical power.
- Followed PRISMA guidance with dual independent reviewers (screening agreement Kappa approximately 0.88) and a third reviewer for disputes.
- Used two complementary quality tools (Cochrane Risk of Bias and the Yates scale tailored to psychological RCTs).
- Conducted subgroup analysis by time point (post-treatment vs three months), sensitivity analyses (random vs fixed effects, leave-one-out), and funnel-plot publication-bias assessment indicating low bias risk and stable results.
- Incorporated the contemporary pain interference outcome that prior reviews omitted.
Limitations
- Substantial clinical heterogeneity across trials (individual vs group, face-to-face vs online delivery, differing intervention durations, and varied pain types and demographics); time-point subgrouping addressed only part of it.
- Not all included studies reported every outcome of interest, reducing the number of trials pooled per outcome and the precision of some estimates.
- Inclusion was restricted to English-language publications, potentially missing relevant studies.
- Quality-assessment tools carry inherent subjectivity, and some trials had unclear or high risk of bias for allocation concealment and attrition.
- The review was not preregistered, which the authors acknowledge as a potential source of bias.
- Most interventions were psychologist-led and follow-up extended only to three months, so longer-term and nurse-delivered effects remain uncertain.
Key Takeaways for Patients
What This Means for You
- 01Acceptance and commitment therapy (ACT) is a talk-therapy approach that helps people live a fuller life alongside pain rather than focusing only on eliminating it.
- 02In this pooled analysis, ACT was linked to meaningful improvements in how much pain interfered with daily life, day-to-day functioning, acceptance of pain, and symptoms of depression and anxiety.
- 03Effects on pain intensity and overall quality of life were present but smaller, and improvements generally lasted at least three months after treatment ended.
- 04ACT is not a cure for chronic pain; the authors describe it as a potentially helpful tool and call for more research in specific pain conditions and with longer follow-up.
- 05Both psychologists and trained nurses may be able to deliver ACT techniques, including in brief or digital formats, though most trials to date were psychologist-led.