Processes underlying smoking cessation among adolescents

Today Marloes Kleinjan defended her doctoral thesis on processes underlying smoking cessation among adolescents.
Smoking habits are often initiated in adolescence. Once adolescents have smoked long enough (and that happens sooner rather than later), they are likely to develop dependency symptoms and chances are high that they will continue smoking into adulthood. Marloes Kleinjan’s thesis explores the development of smoking dependence among adolescents, as well as the process of what underlies motivation and actions related to smoking cessation in this important target population.
The Transtheoretical model (TTM), with the ‘stages of change’ as one of its cores, is well known and very popular in health behaviour change research and interventions. The model has been applied to many health behaviours, but it was developed mostly based on smoking cessation research. TTM was initiated by Prochaska and DiClemente, and a stronghold for TTM research is the Cancer Prevention Research Center in Rhode Island. TTM basically posits that health behaviour change occurs in different distinct ‘stages of change’, i.e. precontemplation, contemplation, preparation, action and maintenance. TTM further argues that different processes of change are important and necessary to help people to proceed through the different stages.
In recent years different studies and reviews argued that the validity of the model’s application to other health behaviours such, especially nutrition and physical activity, is rather doubtful, or just not good enough (see for example papers by Emely de Vet et al.).
Research supporting TTM is mostly cross-sectional research. Such studies only provide evidence for associations between for example processes of change and stages of change. These associations can often not be found in longitudinal or experimental studies.
Marloes Kleinjan’s thesis now indicates that we should also be careful in applying TTM to smoking cessation among youth. In different studies, hardly any evidence could be found that supported the hypothesis that distinct process of change are important for distinct stage transitions.