A planning intervention to quit smoking in single-smoking couples: does partner involvement improve effectiveness?

Objective: Smoking cessation interventions that use implementation intentions have shown promising results. Implementation intentions are if-then plans that specify certain behaviour within a situational context. This study examines whether dyadic planning (i.e., involving a non-smoking partner) is more effective than individual planning in quitting smoking. Design: This longitudinal single-blind randomized controlled trial involves a baseline questionnaire, end-of-day measurements for three weeks, and a follow-up questionnaire after three months. Single-smoking couples were randomized to a dyadic or individual planning condition. After the intervention, which 176 couples received, smokers attempted to quit smoking, and the diary measurements started. Main Outcome Measures: smoking abstinence, number of cigarettes smoked and relationship satisfaction. Results: At follow-up, both planning groups showed similar quit rates (33%, dyadic; 30%, individual) and a similar significant decline in number of cigarettes smoked (almost 50%). For most smokers, the smoking pattern shown in the diary seemed to be indicative of smoking behaviour at follow-up. Relationship satisfaction declined minimally, in both intervention groups and in both smokers and partners. Conclusion: The involvement of a non-smoking partner in the planning did not increase its effectiveness. However, couple participation and daily measurements during a quit attempt could be important components of future interventions.