Wetherell 2011.

Methods	RCT; 2 arms; acceptance and commitment therapy, CBT; post‐treatment and 6 month follow‐up
Participants	End of treatment: n = 99 Start of treatment: n = 114 Sex: 58 F; 56 M Mean age: 54.9 (SD 12.5) Mean years of pain: 15 (SD 35.5) Source = primary care (40%); adverts and newspaper article (40%); pain support groups (10%); various (10%) Diagnosis = mixed chronic pain
Interventions	ACT versus CBT
Outcomes	Primary pain outcome: BPI pain severity Primary disability outcome: BPI interference Primary mood outcome: BDI Catastrophising outcome: none Pain severity: BPI Sub‐scale Disability: BPI Interference Sub‐scale (primary outcome) Disability: MPI General Activity Sub‐scale Depression: BDI‐II Anxiety: PASS Quality of life: SF‐12 physical and mental subscores Treatment Satisfaction Questionnaire
Notes	ACT versus CBT: analyses 1.1, 1.2, 1.3, 2.1, 2.2, 2.3 2011 update search. Yates quality scale: total quality = 32/35, design quality = 24/26, treatment quality = 8/9
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Group randomisation generated by computer
Allocation concealment (selection bias)	Low risk	Staff member who accessed randomisation code had no contact with participants
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Attrition fully reported; several differences between dropouts and completers
Selective reporting (reporting bias)	Low risk	Fully reported
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Assessment staff blind to treatment condition