Do the Transtheoretical Model processes of change, decisional balance and temptation predict stage movement? Evidence from smoking cessation in adolescents.

AIMS: To examine the effects of processes of change (POC) on forward stage movement directly, indirectly through decisional balance and temptation, and total effects as a test of the key hypothesis of the Transtheoretical Model (TTM). DESIGN: Prospective cohort study. SETTING: United Kingdom. PARTICIPANTS: A total of 1160 adolescents aged 13-14 years who were current or former smokers at baseline. MEASUREMENTS: Stage was assessed with the standard algorithm three times, once every 3 months. On each occasion the POC, decisional balance and temptation were measured with the standard questionnaires. Path analysis was used to examine the direct, indirectly mediated and total contribution of POC and the other constructs to stage movement 3 months later. FINDINGS: Four of the 24 analyses showed evidence that the theoretically appropriate POC predicted stage transition, with statistically significant total effects. Effect sizes were small. When the POC were summarized to experiential and behavioural process means, one transition from pre-contemplation was predicted by experiential processes and, contrary to the TTM, one transition predicted by behavioural processes. There was slightly more evidence that decisional balance (attitudes towards smoking) and temptation (ability to resist the urge to smoke) was associated with stage transition. CONCLUSIONS: POC use was not associated generally with stage transition and evidence that effects, if missed, must be modest, giving no support to the central tenet of the TTM.