Beyond ‘planning’: A meta-analysis of implementation intentions to support smoking cessation

Objective: Implementation intentions support behaviour change by encouraging people to link critical situations with appropriate responses. Overall effectiveness for smoking cessation is unknown. This systematic review and meta-analysis aimed to evaluate the effectiveness of implementation intentions for smoking cessation. Methods: Using PRISMA guidelines, six electronic databases were searched (updated Feb 2018) using key terms. Data were pooled for smoking cessation (categorical variable; yes/no) and entered in to random effects models. Analyses assessed: a) effectiveness as a single intervention, and b) effectiveness when included as one of multiple intervention components. Results: Twelve studies were identified. Implementation intentions were effective for smoking cessation at follow-up OR 1.70, CI [1.32, 2.20], p <.001, average 10.7% quit rate for intervention participants (4.9% in controls). Implementation intentions as a single intervention were effective for smoking cessation OR 5.69 , 95% CI [1.39, 23.25], p = 0.02 (average quit rate 14.3% in intervention participants versus 3.6% in controls) and as part of multi-component interventions OR 1.67, 95% CI [1.29, 1.66], p < 0.001 (average quit rate 8.2% in intervention participants versus 5.8% in controls). Conclusions: Implementation intentions are effective at helping smokers quit although the review reported substantial heterogeneity across the limited number of included studies. The present review sets the agenda for future research in this area including longer-term objectively-verified abstinence and identification of potential moderators of effectiveness including population characteristics.