Huber 2003.

Methods	Setting: academic research centre, Germany Recruitment: community volunteers
Participants	225 smokers (102 in relevant arms); 55% F, av age 38, av cpd 28
Interventions	Pharmacotherapy: nicotine gum, 2 or 4 mg 1. 5 x 90‐min weekly meetings. Included contracting, reinforcement, relaxation, skills training 2. Same schedule of meetings, 45‐min only, focus on sharing experiences 3. As 1, no nicotine gum. Not included in this review 4. Wait‐list control for 6 m. Not included in this review
Outcomes	PP abstinence at 12 m Validation: CO ≤ 4 ppm
Source of Funding/CoI	Not specified. No declarations of interest
Notes	Control and intervention fell into same categories for number and duration of sessions.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised, method not described
Allocation concealment (selection bias)	Unclear risk	No details given
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Biochemically validated
Incomplete outcome data (attrition bias) All outcomes	Low risk	31 people attending 2 or fewer meetings not included in analysis. Said to be evenly distributed. Later dropouts included as smokers; 90% of those receiving therapy (excluded wait‐list group 4, who were also excluded from this review) followed up at 12 m.