Health and life

The transtheoretical model of behaviour change was originally developed by Prochaska and DiClemente (1982) as a synthesis of 18 therapies describing the processes involved in eliciting and maintaining change. It is now more commonly known as the stages-of-change model. Prochaska and DiClemente examined these different therapeutic approaches for common processes and suggested a new model of behaviour change based on the following stages:
1 Pre-contemplation: not intending to make any changes.
2 Contemplation: considering a change.
3 Preparation: making small changes.
4 Action: actively engaging in a new behaviour.
5 Maintenance: sustaining the change over time.
These stages, however, do not always occur in a linear fashion (simply moving from 1 to 5) but the theory describes behaviour change as dynamic and not ‘all or nothing’. For example, an individual may move to the preparation stage and then back to the contemplation stage several times before progressing to the action stage. Furthermore, even when an individual has reached the maintenance stage, they may slip back to the contemplation stage over time.
The model also examines how the individual weighs up the costs and benefits of a particular behaviour. In particular, its authors argue that individuals at different stages of change will differentially focus on either the costs of a behaviour (e.g. stopping smoking will make me anxious in company) or the benefits of the behaviour (e.g. stopping smoking will improve my health).
For example, a smoker at the action (I have stopped smoking) and the maintenance (for four months) stages tend to focus on the favourable and positive feature of their behaviour (I feel healthier because I have stopped smoking), whereas smokers in the pre-contemplation stage tend to focus on the negative features of the behaviour (it will make me anxious).
The stages-of-change model has been applied to several health-related behaviours, such as smoking, alcohol use, exercise and screening behaviour (e.g. DiClemente et al. 1991; Marcus et al. 1992). If applied to smoking cessation, the model would suggest the following set of beliefs and behaviours at the different stages:
1 Pre-contemplation: ‘I am happy being a smoker and intend to continue smoking’.
2 Contemplation: ‘I have been coughing a lot recently, perhaps I should think about stop- ping smoking’.
3 Preparation: ‘I will stop going to the pub and will buy lower tar cigarettes’.
4 Action: ‘I have stopped smoking’.
5 Maintenance: ‘I have stopped smoking for four months now’.
This individual, however, may well move back at times to believing that they will continue to smoke and may relapse (called the revolving door schema).
The stages-of-change model is increasingly used both in research and as a basis to develop interventions that are tailored to the particular stage of the specific person concerned. For example, a smoker who has been identified as being at the preparation stage would receive a different intervention to one who was at the contemplation stage. However, the model has recently been criticized for the following reasons (Weinstein et al. 1998; Sutton 2000, 2002a; West 2006):
■ It is difficult to determine whether behaviour change occurs according to stages or along a continuum. Researchers describe the difference between linear patterns between stages which are not consistent with a stage model and discontinuity patterns which are consistent.
■ However, the absence of qualitative differences between stages could either be due to the absence of stages or because the stages have not been correctly assessed and identified.
■ Changes between stages may happen so quickly as to make the stages unimportant.
■ Interventions that have been based on the stages-of-change model may work because the individual believes that they are receiving special attention, rather than because of the effectiveness of the model per se.
■ Most studies based on the stages-of-change model use cross-sectional designs to examine differences between different people at different stages of change. Such designs do not allow conclusions to be drawn about the role of different causal factors at the different stages (i.e. people at the preparation stage are driven forward by different factors than those at the contemplation stage). Experimental and longitudinal studies are needed for any conclusions about causality to be valid.
■ The concept of a ‘stage’ is not a simple one as it includes many variables: current behavi- our, quit attempts, intention to change and time since quitting. Perhaps these variables should be measured separately.
■ The model focuses on conscious decision-making and planning processes. Further it assumes that people make coherent and stable plans.
■ Using the model may be no better than simply asking people, ‘Do you have any plans to try to…?’ or ‘Do you want to…?’.