Comparison 3. Anticonvulsants versus placebo according to length of trial.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Dropouts	16		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
1.1 Up to six weeks	4	198	Risk Ratio (M‐H, Random, 95% CI)	0.67 [0.37, 1.19]
1.2 Over six weeks	12	1477	Risk Ratio (M‐H, Random, 95% CI)	0.99 [0.76, 1.29]
2 Heavy drinking, dichotomous outcome: over six weeks	4	309	Risk Ratio (M‐H, Random, 95% CI)	0.94 [0.67, 1.32]
3 Alcohol use, continuous outcome: drinks/drinking day	11		Mean Difference (IV, Random, 95% CI)	Subtotals only
3.1 Up to six weeks	3	155	Mean Difference (IV, Random, 95% CI)	‐2.14 [‐4.21, ‐0.06]
3.2 Over six weeks	8	971	Mean Difference (IV, Random, 95% CI)	‐1.44 [‐2.46, ‐0.42]
4 Alcohol use, continuous outcome: heavy drinking	12		Std. Mean Difference (IV, Random, 95% CI)	Subtotals only
4.1 Up to six weeks	4	211	Std. Mean Difference (IV, Random, 95% CI)	‐0.45 [‐0.73, ‐0.17]
4.2 Over six weeks	8	918	Std. Mean Difference (IV, Random, 95% CI)	‐0.32 [‐0.53, ‐0.10]
5 Continuous abstinence, dichotomous outcome	8		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
5.1 Up to six weeks	3	141	Risk Ratio (M‐H, Random, 95% CI)	1.23 [0.65, 2.32]
5.2 Over six weeks	5	493	Risk Ratio (M‐H, Random, 95% CI)	1.19 [0.92, 1.54]
6 Abstinence, continuous outcome	8		Mean Difference (IV, Random, 95% CI)	Subtotals only
6.1 Days abstinent (%): up to six weeks	3	107	Mean Difference (IV, Random, 95% CI)	5.82 [‐6.87, 18.51]
6.2 Days abstinent (%): over six weeks	5	707	Mean Difference (IV, Random, 95% CI)	9.98 [0.95, 19.01]
7 Adverse events	11		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
7.1 Withdrawn for medical reasons: up to six weeks	1	57	Risk Ratio (M‐H, Random, 95% CI)	0.22 [0.04, 1.41]
7.2 Withdrawn for medical reasons: over six weeks	10	1332	Risk Ratio (M‐H, Random, 95% CI)	1.52 [0.72, 3.20]