Collins 2004.

Methods	BUPROPION Randomized controlled trial Setting: 2 clinical research sites (Georgetown University Medical Center & State University of New York), USA Recruitment: community volunteers
Participants	555 smokers, >= 10 CPD, excluding history of psychiatric disorder including MDD; 57% F, av. age 46, av. CPD 21
Interventions	1. Bupropion 300 mg/day for 10 w begun 2 w before TQD 2. Placebo Both arms: 7 sessions group behavioural counselling
Outcomes	Abstinence at 6m (prolonged from w2, 7 consecutive days of smoking defined as relapse) Validation: saliva cotinine <= 15 ng/ml
Notes	Replaces Lerman 2002 which reported subset of data. Denominators supplied by 1st author, excludes 114 who withdrew before intervention. Some study details from Lerman 2006. Some genotyping studies combine these participants with those reported in Brown 2007. Funding: National Cancer Institute, National Institute on Drug Abuse, National Center for Research Resources. Treatment provided free of charge by GlaxoSmithKline.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomization was determined by a computer‐generated randomization scheme operated by a senior data manager; stratification was carried out by study site" (Lerman 2006).
Allocation concealment (selection bias)	Low risk	Centrally generated & allocation concealed from counsellors & assessors.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Placebo used but blinding procedure not described in detail
Incomplete outcome data (attrition bias) All outcomes	Low risk	6% lost to follow‐up at 6 month follow‐up; included as smokers.