Jason 2007.

Study characteristics
Methods	RCT, 4 parallel arms
Participants	Diagnostic criteria: CDC 1994 Number of participants: n = 114 Gender: 95 (83.3%) female Age: 43.8 years Earlier treatment: NS Co‐morbidity: 44 (39%) with a current Axis I disorder (depression and anxiety most common). Use of AD not stated Illness duration: > 5 years Work and employment status: 52 (46%) working or studying at least part time, 24% unemployed, 6% retired, 25% on disability Setting: secondary care, but recruitment from different sources Country: USA
Interventions	13 sessions every 2 weeks lasting 45 min Group 1: CBT aimed at showing participants that activity could be done without exacerbating symptoms (n = 29) Group 2: ACT focused on developing individualised and pleasurable activities accompanied by reinforcement of progress (n = 29) Group 3: COG focused on developing strategies to better tolerance, reduce stress and symptoms and lessen self‐criticism (n = 28) Group 4: relaxation treatment, introducing several types of relaxation techniques along with expectations of skill practice (n = 28)
Outcomes	Several outcomes are reported (~25), among others Physical functioning (SF‐36) Fatigue (FSS) Depression (BDI‐II) Anxiety (BAI) Self‐efficacy (self‐efficacy questionnaire) Stress (PSS) Pain (BPI) QoL (QOLS) 6‐MWT Changes in overall health (Clinical Global Impression ‐ Improvement Scale (CGI‐I), score between 1 and 7, where 1 = very much better, 4 = no change) Outcomes assessed at 12 months' follow‐up
Notes	Fidelity ratings and dropout reported across study arms
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Random assignment was done using a random number generator in statistical software (SPSS version 12)"
Allocation concealment (selection bias)	Unclear risk	NS
Blinding (performance bias and detection bias) of participants and personnel?	High risk	Not possible to blind participants or personnel (supervisors) to treatment allocation
Blinding (performance bias and detection bias) of outcome assessors?	High risk	Blinding not possible for self‐reported measurements (e.g. FSS, BPI)
Incomplete outcome data (attrition bias) All outcomes	High risk	Quote: "The average dropout rate was 25%, but it was not significantly different per condition." The statistical analysis used, the best linear unbiased predictor, is a way to avoid taking missing data into account
Selective reporting (reporting bias)	Unclear risk	All primary outcomes stated under Methods were reported; however, as the study protocol is not available, we cannot categorically state that the review is free of selective outcome reporting
Other bias	High risk	Baseline data differences across groups for several important parameters (e.g. physical functioning: ACT group 39.17 (15.65) and relaxation group 53.77 (26.66))