Table 3. Summary of RCTs which demonstrated treatment superior to placebo, for which Relative Risk and Number Needed to Treat values could be calculated.

	Active Treatment (maximum tested dose)	Number of patient Episodes	Benefit Efficacy on Treatment (≥30% improvement VAS	Efficacy on Placebo (≥30% improvement VAS)	RR (95% CI)	NNT (95% CI)
Smoked cannabis
Abrams et al 2007 [40]	Smoked cannabis: 3.56% Δ-9-tetrahydrocannabinol	55 (50)	13/27	6/28	2.17 (0.97 to 4.86)	3.86 (1.98 to 71.11)
Ellis et al 2009 [41]	Smoked cannabis: 8% Δ-9-tetrahydrocannabinol	68 (56)	18/34	7/34	2.57 (1.24 to 5.35)	3.09 (1.98 to 9.30)
Abrams et al [40]+Ellis et al [41]	Combined smoked cannabis studies	122 (106)	31/61	15/61	2.38 (1.38 to 4.10)	3.38 (2.19 to 7.50)