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

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. 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. smoking abstinence, number of cigarettes smoked and relationship satisfaction. 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. 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.