Pharmacological and behavioural interventions to promote smoking cessation in adults with schizophrenia and bipolar disorders: a systematic review and meta-analysis of randomised trials

Objective Smoking in people with serious mental illness is a major public health problem and contributes to significant levels of morbidity and mortality. The aim of the review was to systematically examine the efficacy of methods used to aid smoking cessation in people with serious mental illness. Method A systematic review and meta-analysis of randomised controlled trials to compare the effectiveness and safety of pharmacological and behavioural programmes for smoking cessation in people with serious mental illness. Electronic databases were searched for trials to July 2018. We used the Cochrane Collaboration's tool for assessing the risk of bias. Results Twenty-eight randomised controlled trials were identified. Varenicline increased the likelihood of smoking cessation at both 3 months (risk ratio (RR) 3.56, 95% CI 1.82 to 6.96, p=0.0002) and at 6 months (RR 3.69, 95% CI 1.08 to 12.60, p=0.04). Bupropion was effective at 3 months (RR 3.96, 95% CI 1.86 to 8.40, p=0.0003), especially at a dose of 300 mg/day, but there was no evidence of effect at 6 months (RR 2.22, 95% CI 0.52 to 9.47, p=0.28). In one small study, nicotine therapy proved effective at increasing smoking cessation up to a period of 3 months. Bupropion used in conjunction with nicotine replacement therapy showed more effect than single use. Behavioural and bespoke interventions showed little overall benefit. Side effects were found to be low. Conclusion The new information of this review was the effectiveness of varenidine for smoking cessation at both 3 and 6 months and the lack of evidence to support the use of both bupropion and nicotine products for sustained abstinence longer than 3 months. Overall, the review found relatively few studies in this population.