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

From: Effectiveness of brief interventions as part of the Screening, Brief Intervention and Referral to Treatment (SBIRT) model for reducing the nonmedical use of psychoactive substances: a systematic review

Outcomea Follow up Event rates BI versus no BI Effect Estimate (95% CI) Studies (people) Quality of evidence Comments
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 baselineb[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 baselineb[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 baselineb[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 baselineb[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 baselineb[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 baselineb[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 baselineb[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  
  1. aFor change from baseline data, means for baseline and follow-up timepoints are shown in Table S5, where possible.
  2. bChange in mean analysis calculated as the reported mean at follow-up minus the mean at baseline.
  3. cCalculated from authors’ data at baseline and follow-up, assuming a correlation coefficient of 0.25.
  4. dDrugs other than tobacco, alcohol, cannabis were assessed.
  5. eA few people with alcohol use were included in this analysis.
  6. fComposite outcome: substance use, frequency of use, use-related harms or negatives consequences, intention to reduce substance use, another person concerned with use, use of drug by injection.
  7. gPossible unit of analysis error.
  8. ASSIST, alcohol, smoking and substance involvement screening test; CI, confidence interval; d, days; MD, mean difference; mo, months; RR, risk ratio.