Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Headache relief
RCT	23 people; 16 (70%) with episodic cluster headache, 7 (30%) with chronic cluster headache	Attack free 1 week 11/13 (85%) with ipsilateral greater occipital nerve injection 0/10 (0%) with placebo	P = 0.0001	Effect size not calculated	betamethasone
RCT	23 people; 16 (70%0 with episodic cluster headache, 7 (30%) with chronic cluster headache	Attack free within 72 hours 4 weeks 8/13 (61%) with ipsilateral greater occipital nerve injection 0/10 (0%) with placebo	P = 0.0026	Effect size not calculated	betamethasone