continuous abstinence from weeks 9 to 12 and weeks 9 to 52 (Gonzales et al, 2006; Jorenby et al, 2006; Oncken et al, 2006), and time to smoking relapse. Relapse to smoking after abstinence from weeks 9 to 12 was indicated either by patient-reported cigarette (as little as a single puff) or other nicotine use, or by an expiratory carbon monoxide measurement exceeding 10 p.p.m.
