Using the theory of planned behaviour to understand alcohol and tobacco use in students

This study employed the theory of planned behaviour to investigate the factors underlying intentions to use (time 1, N = 471), and self reported use of alcohol and tobacco (time 2, N = 141) over a 6 month period in a population of students. The TPB provided good predictions of both intentions (alcohol: R2 = 0.167; attitude, and perceived behavioural control (PBC) significant; tobacco: R2 = 0.137, PBC significant) and self reported behaviour (alcohol: R2 = 0.289; tobacco: R2 = 0.423; intentions and PBC significant for both). Descriptive norms but not moral norms explained additional variance in intentions. Implications for furthering our understanding of these behaviours are discussed.