An online randomised controlled trial of mental contrasting with implementation intentions as a smoking behaviour change intervention

Objective: We assessed the effectiveness of mental contrasting with implementation intentions (MCII), an established self-regulatory strategy, as a brief online smoking behaviour change intervention. We expected that MCII would enhance smoking reduction among the highly cigarette dependent because MCII is most effective for challenging pursuits. Design: Participants interested in reducing or quitting smoking were recruited online via Amazon Mechanical Turk. At Time 1, we assessed cigarette dependence using the Cigarette Dependence Scale (CDS-5), then administered one of two brief self-help interventions: MCII (n = 172) or a government-promoted control strategy (n = 174). Participants were invited to complete an online follow-up survey 4 weeks later (Time 2). Main Outcome Measure: At Time 1 and Time 2, we measured recent cigarette smoking with a retrospective, self-report questionnaire. We used these reports to compute smoking reduction scores, with an intent-to-treat approach. Results: MCII increased smoking reduction compared to the control strategy at high, but not low, levels of cigarette dependence. Conclusion: We found preliminary evidence consistent with MCII, delivered as a brief online intervention, as an effective smoking reduction strategy for highly dependent cigarette smokers. Further research is needed on MCII as a smoking behaviour change intervention.