Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Symptom severity
[12] RCT 4-armed trial	203 adults In review [10]	Headache index score (mean of pain ratings: score 0–10 where 10 is most severe pain, recorded in a diary 4 times/day) 6 months with stress management with placebo Absolute results not reported	MD 0.79 95% CI 0.30 to 1.28	Effect size not calculated	stress management
[12] RCT 4-armed trial	203 adults In review [10]	Clinically important improvement (50% or more reduction in headache index score) 17/49 (35%) with stress management 14/48 (29%) with placebo	RR 1.19 95% CI 0.66 to 2.13		Not significant