Objective: To evaluate the predictive value of aspects of the Transtheoretical Model (TTM) of behavior change as applied to smoking cessation in a large-group, community-based cognitive-behavioral intervention.
Research approach: Cognitive-behavioral intervention followed by 3-month assessment of smoking status.
Setting: Regional Outpatient Cancer Centre.
Study participants: A total of 2069 participants in smoking cessation clinics held between 1992 and 1999.
Intervention: Eight 90-min sessions over 4 months utilizing education, self-monitoring, a group quit date, and behaviour modification techniques.
Main outcome measures: Cessation rates at 3 months postquit date. Differences between successful and unsuccessful participants on the baseline TTM variables of: stages of change, processes of change, decisional balance and situational temptations, as well as of precessation demographic, smoking history, and smoking behavior variables.
Results: Nonsmokers at 3 months endorsed using more of only one of the processes of change (Reinforcement Management) more than smokers prior to starting the program. They also endorsed more Cons of Smoking and had a more negative Decisional Balance score. When the variables of tobacco tolerance on the Fagerstrom Test for Nicotine Dependence (FTND), marital status, association with the Cancer Centre, and amount of vigorous exercise were first entered in a logistic regression model, Reinforcement Management and Cons of Smoking continued to be predictive of smoking cessation success, but again none of the other TTM variables added explanatory power.
Conclusions: TTM variables measured prior to program attendance added little predictive value for cessation outcome beyond that explained by demographic and smoking history variables. Future studies may benefit from reassessing the TTM variables at the quit date and the 3-month assessment of smoking status to evaluate how the program impacted these variables.