Understanding adolescent smoking: The role of the Theory of Planned Behaviour and implementation intentions

Abstract

This research examined the power of the Theory of Planned Behaviour (TPB) to predict smoking intentions and smoking behaviour in a sample of adolescents (N = 162). In addition, the role of past smoking behaviour and an implementation intention intervention was assessed. TPB variables and smoking behaviour was assessed by self-report questionnaires given to children (11 and 12 years old) at the beginning of the study (time 1) and again 8 weeks later (time 2). All children received information against smoking and either formed an implementation intention about how, where and when they could resist smoking, or in the control condition how, where and when they could finish all their work at school. The TPB provided good predictions of intentions cross-sectionally (R2 = 0.27) and prospectively (R2 = 0.23) and behaviour prospectively (91% correctly classified). Past behaviour was only significant in the prospective analyses. Implementation intentions produced modest reductions in smoking and smoking initiation compared to the control group. These differences were not significant. Implementation intentions increased the power of attitudes and decreased the power of perceived behavioural control to predict intentions prospectively. Implications for furthering our understanding of smoking initiation in this group are discussed.