Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Quality of life
RCT	60 adults with CFS (Oxford criteria) In review	Proportion of people with a final score on Karnofsky quality-of-life scale of >80 12 months 22/30 (73%) with CBT 8/30 (27%) with usual care	RR 2.75 95% CI 1.54 to 5.32 NNT 3 95% CI 2 to 5	Moderate effect size	CBT
RCT 3-armed trial	153 adults with CFS (CDC criteria) In review	Change in quality-of-life score (assessed by short-form [SF]-36 questionnaire) 12 months with group CBT with usual care Absolute results not reported	Absolute difference 4.36 for group CBT v usual care 95% CI 0.72 to 7.97 P = 0.019	Effect size not calculated	CBT
RCT 3-armed trial	153 adults with CFS (CDC criteria) In review	Change in quality-of-life score (assessed by SF-36 questionnaire) 12 months with group CBT with education and support Absolute results not reported	Absolute difference +3.16 for group CBT v education and support 95% CI –0.05 to +6.38 P = 0.5		Not significant
RCT 4-armed trial	90 adults with a mean age of 39.6 years who fulfilled diagnostic criteria for CFS (not further defined) In review	Mean visual analogue score 7 months (3 months after completion of treatment) 469 with CBT plus placebo 477 with usual care plus placebo	Significance not assessed
RCT	63 adolescents aged 11–18 years with CFS (CDC or Oxford criteria) In review	Mean work and social adjustment score 6 months post treatment 2.5 with family-focused CBT 3.3 with psycho-education	Adjusted mean difference –0.48 95% CI –1.55 to +0.59 P = 0.37 Mean difference adjusted for associated baseline values		Not significant
Mental health
RCT 3-armed trial	153 adults with CFS (CDC criteria) In review	Change in mental health score (assessed by SF-36 questionnaire) with group CBT with usual care Absolute results not reported	Absolute difference 4.35 for group CBT v usual care 95% CI 0.72 to 7.97 P = 0.019	Effect size not calculated	CBT
RCT 3-armed trial	153 adults with CFS (CDC criteria) In review	Change in mental health score (assessed by SF-36 questionnaire) with group CBT with education and support Absolute results not reported	Absolute difference +3.16 for group CBT v education and support 95% CI –0.05 to +6.38 P = 0.5		Not significant
RCT 3-armed trial	153 adults with CFS (CDC criteria) In review	Anxiety (assessed by Hospital Anxiety and Depression scale [HADS] score) with group CBT with usual care Absolute results not reported	Absolute difference –1.27 for group CBT v usual care 95% CI –2.52 to –0.02 P = 0.045 Result is of borderline significance	Effect size not calculated	CBT
RCT 3-armed trial	153 adults with CFS (CDC criteria) In review	Anxiety (assessed by HADS score) with group CBT with education and support Absolute results not reported	Absolute difference –0.51 for group CBT v education and support 95% CI –1.70 to +0.68		Not significant
RCT 3-armed trial	153 adults with CFS (CDC criteria) In review	Depression (assessed by HADS score) with group CBT with usual care Absolute results not reported	Absolute difference –0.56 for group CBT v usual care 95% CI –1.69 to +0.58		Not significant
RCT 3-armed trial	153 adults with CFS (CDC criteria) In review	Depression (assessed by HADS score) with group CBT with education and support Absolute results not reported	Absolute difference –0.13 for group CBT v education and support 95% CI –1.13 to +0.87		Not significant
RCT 4-armed trial	641 adults with CFS (Oxford criteria)	Depression (assessed by HADS score) 52 weeks 6.2 with CBT 7.2 with specialist medical care	P = 0.0003	Effect size not calculated	CBT
RCT 4-armed trial	641 adults with CFS (Oxford criteria)	Anxiety (assessed by HADS score) 52 weeks 6.8 with CBT 8.0 with specialist medical care	P = 0.0003	Effect size not calculated	CBT