Comparison 5. Motivational interviewing versus standard care.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Leaving the study early: 1. Lost to treatment	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
1.1 3 months	1	62	Risk Ratio (M‐H, Random, 95% CI)	0.89 [0.30, 2.61]
1.2 6 months	1	62	Risk Ratio (M‐H, Random, 95% CI)	1.71 [0.63, 4.64]
2 Leaving the study early: 2.Lost to evaluation	9		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
2.1 By 3 months	7	457	Risk Ratio (M‐H, Random, 95% CI)	1.08 [0.69, 1.70]
2.2 By 6 months	4	164	Risk Ratio (M‐H, Random, 95% CI)	0.85 [0.29, 2.53]
2.3 By 12 months	3	247	Risk Ratio (M‐H, Random, 95% CI)	0.92 [0.44, 1.92]
3 Adverse event: 1. Death, due to all causes, by 18 months	1	49	Risk Ratio (M‐H, Random, 95% CI)	1.04 [0.07, 15.73]
4 Substance use: 1. Using substances ‐ by class of drug ‐ by about 12 months	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
4.1 Alcohol abuse/dependence	1	52	Risk Ratio (M‐H, Random, 95% CI)	1.35 [0.62, 2.92]
4.2 Amphetamine abuse/dependence	1	19	Risk Ratio (M‐H, Random, 95% CI)	0.24 [0.03, 1.92]
4.3 Cannabis abuse/dependence	1	62	Risk Ratio (M‐H, Random, 95% CI)	0.77 [0.49, 1.21]
5 Substance use: 2. Polydrug consumption levels ‐ by 12 months (OTI, high = poor)	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
5.1 By 3 months	1	89	Mean Difference (IV, Random, 95% CI)	‐0.41 [‐0.91, 0.09]
5.2 By 12 months	1	89	Mean Difference (IV, Random, 95% CI)	‐0.07 [‐0.56, 0.42]
6 Substance use: 3. Any change ‐ not abstinent or not improved on all substances ‐ by 12 months	1	25	Risk Ratio (M‐H, Random, 95% CI)	0.51 [0.24, 1.10]
7 Substance use: 4. Any change ‐ not abstaining from alcohol	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
7.1 By 3 months	1	28	Risk Ratio (M‐H, Random, 95% CI)	0.52 [0.26, 1.03]
7.2 By 6 months	1	28	Risk Ratio (M‐H, Random, 95% CI)	0.36 [0.17, 0.75]
8 Substance use: 5. Change in cannabis use from baseline (T0) (lower scores indicate better outcome)	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
8.1 3 months	1	62	Mean Difference (IV, Random, 95% CI)	‐12.81 [‐23.05, ‐2.57]
8.2 6 months	1	62	Mean Difference (IV, Random, 95% CI)	‐9.64 [‐18.05, ‐1.23]
8.3 12 months	1	62	Mean Difference (IV, Random, 95% CI)	‐5.82 [‐14.77, 3.13]
9 Substance use: 6. Cannabis consumption past 30 days (ASI, high = poor) (skewed data)			Other data	No numeric data
9.1 By 3 months			Other data	No numeric data
9.2 By 6 months			Other data	No numeric data
10 Substance use: 7. Engagement with substance misuse treatment at 3 months (SATS, low = poor))	1	59	Mean Difference (IV, Random, 95% CI)	0.30 [‐0.47, 1.07]
11 Substance use: 8. Average scores (OTI, high = poor) (skewed data)			Other data	No numeric data
11.1 Alcohol			Other data	No numeric data
11.2 Amphetamine			Other data	No numeric data
11.3 Cannabis			Other data	No numeric data
11.4 Polydrug use			Other data	No numeric data
12 Substance use: 9. Other measures of alcohol use (skewed data)			Other data	No numeric data
12.1 Alcohol volume (AUI subscale)			Other data	No numeric data
12.2 Drinking days ‐ by 6 months			Other data	No numeric data
12.3 Alcohol consumption, last 30 days (ASI) ‐ 3 months			Other data	No numeric data
12.4 Alcohol consumption, last 30 days (ASI) ‐ 6 months			Other data	No numeric data
12.5 Alcohol use (AUDIT) ‐ 3 months			Other data	No numeric data
12.6 Alcohol use (CAUS) ‐ 3 months			Other data	No numeric data
12.7 Drug use (CDUS) ‐ 3 months			Other data	No numeric data
12.8 Drug use (SDS) ‐ 3 months			Other data	No numeric data
13 Mental state: 1. Average scores (SCL‐90‐R, high = poor) ‐ by 3 months	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
13.1 General severity index	1	30	Mean Difference (IV, Random, 95% CI)	‐0.19 [‐0.59, 0.21]
13.2 Positive symptom distress index	1	30	Mean Difference (IV, Random, 95% CI)	‐0.19 [‐0.66, 0.28]
13.3 Positive symptom scores	1	30	Mean Difference (IV, Random, 95% CI)	‐4.20 [‐18.72, 10.32]
14 Mental state: 2. Average scores (PANSS negative symptoms, high = poor)	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
14.1 By 3 months	1	62	Mean Difference (IV, Random, 95% CI)	‐0.10 [‐2.06, 1.86]
14.2 By 6 months	1	62	Mean Difference (IV, Random, 95% CI)	0.0 [‐1.80, 1.80]
15 Mental state: 3. Average scores (PANSS positive symptoms, high = poor)	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
15.1 3 months	1	62	Mean Difference (IV, Random, 95% CI)	‐0.30 [‐2.55, 1.95]
15.2 6 months	1	62	Mean Difference (IV, Random, 95% CI)	‐0.10 [‐2.58, 2.38]
16 Mental state: 4. Average score (HADS, BSI, high = poor) (skewed data) ‐ by 3 months			Other data	No numeric data
16.1 HADS‐A, Anxiety			Other data	No numeric data
16.2 HADS‐D, Depression			Other data	No numeric data
16.3 BSI			Other data	No numeric data
17 Global state: 1. Average score (GAF, low = poor)	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
17.1 3 months	1	51	Mean Difference (IV, Random, 95% CI)	‐0.40 [‐3.53, 2.73]
17.2 6 months	1	49	Mean Difference (IV, Random, 95% CI)	‐1.0 [‐4.81, 2.81]
17.3 12 months	1	54	Mean Difference (IV, Random, 95% CI)	2.30 [‐1.30, 5.90]
18 Global state: 2. Forensic measures ‐ average number of crimes (skewed data)			Other data	No numeric data
18.1 6 months			Other data	No numeric data
18.2 12 months			Other data	No numeric data
19 Social functioning: 1. Average score (OTI, high = poor)	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
19.1 By 6 months	1	102	Mean Difference (IV, Random, 95% CI)	‐0.71 [‐2.76, 1.34]
19.2 By 12 months	1	102	Mean Difference (IV, Random, 95% CI)	‐1.42 [‐3.35, 0.51]
20 Social functioning: 2. Average score (SOFAS, low = poor)	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
20.1 3 months	1	62	Mean Difference (IV, Random, 95% CI)	0.10 [‐3.02, 3.22]
20.2 6 months	1	62	Mean Difference (IV, Random, 95% CI)	‐0.10 [‐3.51, 3.31]
20.3 12 months	1	62	Mean Difference (IV, Random, 95% CI)	2.70 [‐1.08, 6.48]
21 Service use: Hospital admission to 12 months	1	62	Risk Ratio (M‐H, Random, 95% CI)	0.87 [0.42, 1.80]
22 Service use: Lost to first aftercare appointment	1	93	Risk Ratio (M‐H, Random, 95% CI)	0.69 [0.53, 0.90]