The application of theories of behaviour change to addictive behaviour
The Theory of Planned Behaviour (TPB) sees attempts to abstain from dependency behaviours as due to factors supporting decision making, rather than predisposing factors, but with an added component where addicts need confidence in their abilities and available resources to quit. TPB has three components: behavioural beliefs, involving the subjective probability that behaviour will produce abstention; normative beliefs, involving the degree of perceived social pressure to quit; control beliefs, involving individual beliefs about the ability to abstain. TPB assesses an individual’s motives for continuing dependency and their resolve to abstain. The higher their level of perceived behavioural control, the more likely they’ll quit. Prochaska’s six-stage model of behaviour change details the process of changing from unhealthy to healthy behaviours. (1) Pre-contemplation involves recognition of unhealthy behaviour, but with no compulsion to address it. (2) Contemplation involves an admission that action is needed. (3) Preparation involves planning for how such action will occur. (4) Action involves putting the plan into action, which usually involves cutting down or withdrawing from the dependency behaviour. (5) Maintenance involves using strategies to prevent relapse, such as focusing on the benefits of withdrawal. (6) Termination involves reaching a state where temptation is no longer experienced.
Fig 17.5 Theory of Planned Behaviour (Ajzen, 1991)
Velicer et al. (2007) assessed the effectiveness of Prochaska’s six-stage model of behaviour change to addictive behaviour. A meta-analysis of 5 studies involving 58,454 participants was conducted that investigated the success levels of smoking cessation programmes that were based upon Prochaska’s model. It was found that there was a 22—26 per cent success rate in participants having maintained cessation of smoking behaviour 6 months after first withdrawing from smoking behaviour. The researchers found no demographic differences in success rates, such as gender or age related factors, which suggests the programme is widely applicable to all types of people. It was discovered though that success was generally dependent on how frequent smoking behaviour had originally been. As the success levels compare favourably with other types of intervention in addressing nicotine addiction, it suggests Prochaska’s model can be regarded as being effective.
• Oh & Hsu (2001) used a questionnaire to assess gamblers’ previous gambling behaviour, their social norms, attitudes, perceived behavioural control (such as perceived gambling skills and levels of self-control), along with behavioural intentions. A positive correlation was found between attitudes and behavioural intentions and actual behaviour, supporting the TPB.
• Walker et al. (2006) used interviews to assess whether theory of planned behaviour could explain gambling behaviour. It was found that behavioural beliefs and normative beliefs were important but that perceived behavioural control was not. Intention was, however, found to be a good predictor of behavioural change. This supports some elements of the TPB but not others.
• Aveyard et al. (2009) assessed the effectiveness of Prochaska’s model, finding that there was no increase in effectiveness of cessation from smoking behaviour if an intervention was tailored to the stages of change an individual was in. This contradicts the findings of Velicer.
The TPB is used widely in health psychology and health economics (which examines the cost effectiveness of treatments). This suggests that practitioners acknowledge its validity and deem its predictive power as useful.
A strength of the TPB is its acknowledgement of the role of peers in influencing behaviour. This influence does not stop once an addiction is developed and therefore needs to be considered in predicting outcomes of behaviour change programmes.
Looking at change as a series of stages means that interventions can be designed to match the stage of Prochaska’s model that an individual is currently in, with some evidence to support the effectiveness of this.
There is no consideration of emotion within the TPB, which can influence the likelihood of behavioural change. This is especially the case with addiction, which is a vulnerable state influenced by mood.
Both models rely on self-report measures to assess their effectiveness, which could be problematic, as addicts are often not in a state to honestly appraise their own behaviour and frame of mind.
Research support for Prochaska’s model is mixed, lowering support for the explanation. It may be that wide individual differences mean the model suits some, but not all cases of addiction.
Both models have applications as therapies to address addiction. Prochaska’s model allows interventions to be tailored to which stage of change an individual is in, while the TPB is used to decide whether an intervention may be effective, which means money, time and effort can be saved if it will not be effective.