Comparison 1. Δ⁹‐Tetrahydrocannabinol (THC) preparation versus placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Participants abstinent at end of treatment	3	305	Risk Ratio (M‐H, Random, 95% CI)	0.98 [0.64, 1.52]
2 Participants experiencing adverse effects	3	318	Risk Ratio (M‐H, Random, 95% CI)	1.02 [0.89, 1.17]
3 Participants withdrawn due to adverse effects	3	318	Risk Ratio (M‐H, Random, 95% CI)	2.72 [0.51, 14.59]
4 Completion of scheduled treatment	4	369	Risk Ratio (M‐H, Random, 95% CI)	1.10 [0.88, 1.37]