Table 1.

Study and participant descriptive characteristics of included studies

Author, year; design; funding	Summary of included participants; incentives	Summary of excluded participants	Demographics: mean age (range) of randomized participants; Sex (% female, intervention versus control)	Country	Setting	Number of participants screened	Randomized participants
							I	C
BI versus no BI
Baer et al., 2007 [33]; Single site RCT; Government funding	127 participants who were homeless and with one or more binge drinking episodes or used illicit drugs four or more times in the past 30 days; Incentives offered for enrolling and attending BI and follow-up sessions	Those receiving alcohol or drug treatment in the past 30 days.	17.9 y (13 to 19 y); 44%a	United States	Nonprofit, faith-based drop-in center	254	75	52
Humeniuk et al., 2008 [35]; Multisite RCT; WHO and in-kind contributions and government grants from individual sites	731 (Australia n = 171, Brazil n = 165, India n = 177, USA n = 218) participants aged 16 to 62 y with a fixed address who scored in the moderate risk range for cannabis, cocaine, amphetamine stimulants, or opioids; Incentives offered for attending BI session and follow-up sessions	Those pending incarceration, with severe behavior, with past-month drug or alcohol treatment, or unable to attend the follow-up appointment.	31.4 y (16 to 62 y); 27.9%a	Australia, United States, Brazil, and India	One primary, urban general health outpatient hospital setting (Brazil); 31 primary, urban, general health-care units/clinics (Brazil, USA); one walk-in clinic associated with a drug treatment program (USA); several general medicine and dental urban clinics (USA); three clinics/centers specializing in sexually transmitted diseases (Australia, Brazil).	NR	372	359
BI versus Written Information
Bernstein et al., 2009 [34]; Single site RCT; Government funding	210 participants who reported ‘3 to 5 days per month of cannabis use were included; Incentives offered for enrolling and attending follow-up sessions	Those institutionalized, in custody, in residential treatment, receiving a rape exam or were evaluated for suicide precautions.	Mean NR (14 to 21 y); 63.2% versus 67.6%	United States	Pediatric emergency department in an urban academic hospital.	7,804	68	71
Zahradnik et al., 2008 [37]; Cluster RCT (randomization by hospital ward); Government funding	126 participants (2 hospitals; 17 randomized wards) who consumed opioids, anxiolytics, hypnotics and sedatives, or caffeine with addiction potential for more than 60 days in the last 3 months or met criteria for DSM-IV dependence or abuse; Incentives offered for enrolling and attending BI and follow-up sessions	Those using opioids for cancer, with a terminal disease, with dependence on or use of illegal drugs, or receiving substance use treatment.	55.13 y (18 to 69 y); 64.9% versus 60%	Germany	Two hospitals (general and university); internal, surgical, and gynecological wards	6,042	NR	NR
Bernstein et al., 2005 [17]; Single-site RCT; Government funding	1,175 participants who self-reported use of cocaine and/or heroin in the last 30 days, and scored ≥3 on the DAST instrument; Incentives offered for enrolling and attending follow-up sessions	Those in drug use treatment or protective custody.	Mean NR (>18 y); 30.6% versus 28.2%	United States	Three walk-in clinics (urgent care, women’s clinic, homeless clinic) at an urban teaching hospital	23,669	590	585

^aPercent female in total randomized population; information by group not reported.

BI, brief intervention; C, comparison group; DAST, drug abuse screening test; I, intervention group; NR, not reported; RCT, randomized controlled trial; y, year.