Signor 2013.

Study characteristics
Methods	Study design: Randomized controlled trial Country: Brazil Setting: Telephone‐based intervention Eligibility criteria: Included were self‐reported alcohol users from Brazil who had consumed alcohol in the past month and who were seeking help for alcohol use problems through a hotline or a health provider. Excluded were individuals who were unable to answer interview questions due to cognitive difficulties or the effects of alcohol/drugs and those who could not be contacted for a follow‐up interview. Duration of follow‐up: 6‐months Informed consent: Not reported Ethical approvals: Universidade Federal de Ciencias de Saude de Porto Alegre (UFCSPA) Ethics Committee
Participants	Sample size: 637 (293 intervention, 344 control) Description of the target population: Help‐seeking individuals in general population Age: 27 years (Range 21‐37) Sex: 29% female Race/Ethnicity: Not reported Marital status: 30% married or cohabitating Harmful alcohol use (baseline): 84% met criteria for dependence Co‐occurring disorders: Not reported
Interventions	Type: Non‐pharmacologic Description: Brief motivational intervention including self‐help material sent by mail, a 20‐minute brief motivational interview session by phone along with a 10‐minute assessment, and 7 follow‐up calls over a 6‐month period Duration and frequency: One 30‐minute session and 7 follow‐up calls at 1 day, 3 days, 7 days, 1 month, 2 months, 3 months and 6 months Delivery and provider: Trained university students from health programs Comparison group: Necessary advice provided by phone from trained university students from health programs and self‐help material sent by mail
Outcomes	Primary outcome(s): Abstinence Primary outcome measurement tool(s): Not reported Secondary outcome(s): Not reported Secondary outcome measurement tool(s): N/A Time points: 6‐months
Notes	Study funding and conflicts of interest: Brazilian National Secretariat on Drug Policies (Secretaria Nacional Antidrogas, SENAD), Associacao Mario Tannhauser de Ensino Pesquisa e Assistencia (AMTEPA), Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Coordenacao de Aperfeicoamento de Pessoal d Nivel Superior Linked study records: None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Group allocation was performed using a Microsoft H software application that applied a random number technique." Pg. 255
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and personnel cannot be blinded for this type of intervention
Blinding of outcome assessment (detection bias) All outcomes	High risk	Outcomes reported by participant not blind to intervention "Counselors were blinded to the collection of follow‐up data by a random assignment that used scripts to guide the telephone interviews." Pg. 256
Incomplete outcome data (attrition bias) All outcomes	High risk	"Based on continuous abstinence time and the ITT principle, in which dropouts are considered people who relapse, a Cox proportional hazards model detected a significant difference between the BMI and control groups" Pg. 256 "The study attrition rate was 76.9% (490 participants dropped out)." Pg. 256
Selective reporting (reporting bias)	Unclear risk	Protocol not available