Table 4 Evidence table for brief intervention (BI) versus no BI in participants screened for at-risk substance use

PRIMARY OUTCOMES

Substance use

Not reported in any studies

n/a

n/a

Not estimable

0 (0)

n/a

Frequency of use

Change in days of use - Cannabis

1 mo

-3.7 versus -6.1 d (fewer d at 1 mo)

MD 2.40 (-3.80 to 8.61)^c

1 (89)

Very Low

(+) value for MD means fewer days of use with control

Self-report, past 30 d

Change in mean from baseline^b[33]

3 mo

-2.6 versus -5.9 d (fewer d at 3 mo)

MD 3.30 (-2.84 to 9.44)^c

1 (89)

Very Low

Change in days of use - Other drugs ^d

1 mo

-2.3 versus -3 d (fewer d at 1 mo)

MD 0.70 (-2.95 to 4.35)^c

1 (89)

Very Low

Self-report, past 30 d.

3 mo

-2.8 versus -2.3 d (fewer d at 3 mo)

MD -0.50 (-4.30 to 3.30)^c

1 (89)

Very Low

Change in mean from baseline^b[33]

Change in days abstinent ^e

1 mo

3.7 versus 6.4 d (more d at 1 mo)

MD -2.70 (-8.21 to 2.81)^c

1 (89)

Very Low

(-) value for MD means more days abstinent with control

Self-report, past 30 d.

Change in mean from baseline^b[33]

3 mo

2.7 versus 6 d (more d at 3 mo)

MD -3.30 (-8.73 to 2.13)^c

1 (89)

Very Low

Quantity of use

Not reported in any studies

n/a

n/a

Not estimable

0 (0)

n/a

User-related harms or negative consequences of use

Not reported in any studies

n/a

n/a

Not estimable

0 (0)

n/a

Positive behavior change

Not reported in any studies

n/a

n/a

Not estimable

0 (0)

n/a

Decision to attend treatment

Not reported in any studies

n/a

n/a

Not estimable

0 (0)

n/a

Composite outcome

ASSIST Tool Score ^f - All substances

3 mo

-7.8 versus -4.6 (fewer points at 3 mo)

MD -3.20, 95% CI (-6.77 to 0.37)

1 (628)

Low

Higher score = higher substance involvement.

Sum score, range 0 to 27+ points.

(-) value for MD means greater reduction in change score with BI

Change in means from baseline^b[35]

SECONDARY OUTCOMES

Use of different substances

Not reported in any studies

n/a

n/a

Not estimable

0 (0)

n/a

Intention to reduce use

Not reported in any studies

n/a

n/a

Not estimable

0 (0)

n/a

Other health measures

Use of drop-in centre services

1 mo

0.9 versus -0.2 d (more versus fewer d)

MD 1.10 (-1.88 to 4.08)^cg

1 (89)

Very Low

(+) value for MD means greater use with BI

Objective, past 30 d.

Change in means from baseline^b[33]

3 mo

−1.1 versus -1 d (fewer d at 3 mo)

MD -0.10 (-3.23 to 3.03)^cg

1 (89)

Very Low

Use of drop-in additional services

1 mo

0 versus 0.1 d (more d at 1 mo)

MD -0.10 (-0.72 to 0.52)^cg

1 (89)

Very Low

Objective, past 30 d.

Change in means from baseline^b[33]

3 mo

0.5 versus -0.1 d (more versus fewer d)

MD 0.60 (-0.15 to 1.35)^cg

1 (89)

Very Low

Use of other agency services

1 mo

−2.4 versus -7 d (fewer d at 1 mo)

MD 4.60 (-5.05 to 14.25)^cg

1 (89)

Very Low

Self-report, past 30 d.

Change in means from baseline^b[33]

3 mo

−3.4 versus -8.2 d (fewer d at 3 mo)

MD 4.80 (-4.44 to 14.04)^cg

1 (89)

Very Low

ADVERSE OUTCOMES

Not reported in any studies

n/a

n/a

Not estimable

0 (0)

n/a