Comparison 1. Mindfulness versus no treatment.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 Continuous abstinence at post‐treatment	1	112	Risk Ratio (M‐H, Random, 95% CI)	0.96 [0.44, 2.14]
1.2 Continuous abstinence at follow‐up	1	112	Risk Ratio (M‐H, Random, 95% CI)	1.04 [0.54, 2.01]
1.3 Percentage days with substance use at post‐treatment	4	248	Std. Mean Difference (IV, Random, 95% CI)	0.05 [‐0.37, 0.47]
1.4 Percentage days with substance use at follow‐up	3	167	Std. Mean Difference (IV, Random, 95% CI)	0.21 [‐0.12, 0.54]
1.5 Consumed amount at post‐treatment	3	221	Std. Mean Difference (IV, Random, 95% CI)	0.10 [‐0.31, 0.52]
1.6 Consumed amount at follow‐up	2	142	Std. Mean Difference (IV, Random, 95% CI)	0.33 [0.00, 0.66]
1.7 Craving intensity at post‐treatment	2		Std. Mean Difference (IV, Random, 95% CI)	Subtotals only
1.8 Treatment acceptability (attrition)	21	1087	Risk Ratio (M‐H, Random, 95% CI)	1.04 [0.77, 1.40]
1.9 Treatment acceptability (attrition): sensitivity analysis (fixed‐effects model)	21	1087	Risk Ratio (M‐H, Fixed, 95% CI)	1.13 [0.84, 1.50]