Depression and medication adherence among breast cancer survivors: bridging the gap with the theory of planned behaviour

Evidence suggests that more depressed breast cancer patients will less likely adhere to treatment plans. This study presents evidence that the theory of planned behaviour mediates the relation between depression and intentions to adhere to treatment plans and between depression and lack of adherence to medication regime. Two hundred and thirteen women undergoing breast cancer treatment participated in this study. Measures of depressive symptoms and planned behaviour variables were collected at the first time point; measures of medication adherence were collected at the second time point. Structural equation models were utilised to fit the data to the proposed models. Depressive symptoms were significantly correlated to both intentions and medication adherence. In support of hypotheses, the relation between depressive symptoms and treatment intention was mediated by attitudes towards health maintenance plans. The relation between depressive symptoms and medication adherence was fully mediated by the planned behaviour process. Conditions under which treatment intentions and perceptions of control in adhering to treatment were most related to medication adherence were elucidated. The results point to avenues for interventions to increase medication adherence among breast cancer patients. Manipulating attitudes and perceptions of control towards treatment plans will potentially serve to increase medication adherence.     

The theory of planned behaviour and breast self-examination: Assessing the impact of past behaviour,context stability and habit strength

This study applied the theory of planned behaviour (TPB) to the prediction of breast self-examination (BSE) intentions and behaviour, and tested whether the frequency of past behaviour and context stability moderates intention–behaviour and habit–behaviour relations. Seventy-seven females completed measures of the TPB, frequency of past behaviour, context stability and habit strength (Self-Report Habit Index). BSE behaviour was assessed at 1-month follow-up (n?=?66). The TPB explained 33% of the variance in BSE intentions and 11% of the variance in time 2 BSE. The frequency of past behaviour moderated the intention–behaviour relationship such that the intention was only positively related to time 2 BSE behaviour when the frequency of past behaviour was low. Context stability and the combination of the frequency of past behaviour?×?context stability moderated the habit–behaviour relationship such that habit strength was only positively related to time 2 BSE behaviour when context stability and the combination of frequency of past behaviour?×?context stability were high. The results are consistent with the proposal that behaviours that are performed frequently in stable contexts are predominantly under the control of habitual processes, whereas behaviours that are performed infrequently in unstable contexts are predominantly under the control of intentional processes.     

The theory of planned behaviour: Reactions and reflections

The seven articles in this issue, and the accompanying meta-analysis in Health Psychology Review [McEachan, R.R.C., Conner, M., Taylor, N., & Lawton, R.J. (2011). Prospective prediction of health-related behaviors with the theory of planned behavior: A meta-analysis. Health Psychology Review, 5, 97–144], illustrate the wide application of the theory of planned behaviour [Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179–211] in the health domain. In this editorial, Ajzen reflects on some of the issues raised by the different authors. Among the topics addressed are the nature of intentions and the limits of predictive validity; rationality, affect and emotions; past behaviour and habit; the prototype/willingness model; and the role of such background factors as the big five personality traits and social comparison tendency.     

Predicting sun-protective intentions and behaviours using the theory of planned behaviour: a systematic review and meta-analysis

Objective: To synthesise theory of planned behaviour (TPB) relationships, using meta-analysis, and test the predictive utility of the model for sun protection behaviour.

Design: Thirty-eight samples were identified via database/manual searches and academic society posts based on the criteria: measuring sun-protective intentions and/or prospective behaviour; using the TPB/theory of reasoned action as a basis of measurement; and providing bivariate correlations for at least one relevant TPB association.

Main outcome measures: Sun-protective intentions and behaviours.

Results: The sample-weighted average effects were moderate-to-strong with attitudes showing the strongest association with intention (r+ = 0.494), followed by perceived behavioural control (PBC; r+ = 0.451), and subjective norm (r+ = 0.419). Intentions showed a stronger association with prospective behaviour (r+ = 0.486) compared to PBC (r+ = 0.314). A total of 39% of variance in intentions and 25% of variance in behaviour were explained. Publication bias was not evident. Moderator analyses showed that TPB associations were stronger when measures specified the Target, Action, Context and Time; in non-student samples; and when follow-up exceeded two weeks.

Conclusion: Despite recent criticism, this review shows that the TPB explains a large amount of variance in sun protection and that TPB associations are robust across different populations.     

Sleep hygiene behaviours: An application of the theory of planned behaviour and the investigation of perceived autonomy support,past behaviour and response inhibition

This study investigated the sleep hygiene behaviour of university students within the framework of the Theory of Planned Behaviour (TPB [Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179–211.]), and examined the predictive validity of additional variables including perceived autonomy support, past behaviour and response inhibition. A total of 257 undergraduate students from an Australian university were administered two online questionnaires at two time points. At time 1, participants completed the TPB questionnaire and the Go/NoGo task as a measure of response inhibition. A week later at time 2, participants completed a questionnaire measuring the performance of sleep hygiene behaviours. Multiple and hierarchical regression analyses showed that the TPB model significantly predicted intention and behaviour. Although intention and perceived behavioural control were statistically significant in predicting behaviour, past behaviour and response inhibition accounted for more variance when added to the TPB model. Subjective norm was found to be the strongest predictor of intention implying the importance of normative influences in sleep hygiene behaviours. Response inhibition was the strongest predictor of behaviour, reinforcing the argument that the performance of health protective behaviours requires self-regulatory ability. Therefore, interventions should be targeted at enhancing self-regulatory capacity.     

Predictors of physical activity among rural and small town breast cancer survivors: An application of the theory of planned behaviour

The primary objective of this study was to investigate the utility of the two-component theory of planned behaviour (TPB) in understanding physical activity intentions and behaviour in rural and small town breast cancer survivors. The secondary objective was to elicit the most common behavioural, normative and control beliefs of rural and small town survivors regarding physical activity. Using a cross-sectional survey design, 524 rural and small town breast cancer survivors completed a mailed survey that assessed physical activity and TPB variables. Physical activity intention explained 12% of the variance in physical activity behaviour (p?相似文献   

Intentions to participate in counselling among front-line,at-risk Irish government employees: an application of the theory of planned behaviour

ABSTRACT

The study set out to examine intentions to engage in counselling among at-risk Irish government employees and the differential utility of two alternative theory of planned behaviour (TPB) models of behaviour to explain intentions to participate in counselling. Individuals (N=259) employed in a front-line, at-risk occupation for the Irish government completed a TPB-based questionnaire. Quantitative analyses revealed that participants held positive to neutral intentions to participate in counselling, irrespective of gender. The original TPB model explained 49.9% of variance in intentions whereas an alternative TPB model, splitting the perceived behavioural control (PBC) construct between its internal and external control components, explained a further 8.9% of variance. Furthermore, self-efficacy was found to be the strongest predictor of intentions. This study therefore supports the use of the TPB in understanding counselling-seeking behaviour.     

Predicting sugar-sweetened behaviours with theory of planned behaviour constructs: Outcome and process results from the SIPsmartER behavioural intervention

Objective: Guided by the theory of planned behaviour (TPB) and health literacy concepts, SIPsmartER is a six-month multicomponent intervention effective at improving SSB behaviours. Using SIPsmartER data, this study explores prediction of SSB behavioural intention (BI) and behaviour from TPB constructs using: (1) cross-sectional and prospective models and (2) 11 single-item assessments from interactive voice response (IVR) technology.

Design: Quasi-experimental design, including pre- and post-outcome data and repeated-measures process data of 155 intervention participants.

Main Outcome Measures: Validated multi-item TPB measures, single-item TPB measures, and self-reported SSB behaviours. Hypothesised relationships were investigated using correlation and multiple regression models.

Results: TPB constructs explained 32% of the variance cross sectionally and 20% prospectively in BI; and explained 13–20% of variance cross sectionally and 6% prospectively. Single-item scale models were significant, yet explained less variance. All IVR models predicting BI (average 21%, range 6–38%) and behaviour (average 30%, range 6–55%) were significant.

Conclusion: Findings are interpreted in the context of other cross-sectional, prospective and experimental TPB health and dietary studies. Findings advance experimental application of the TPB, including understanding constructs at outcome and process time points and applying theory in all intervention development, implementation and evaluation phases.     

Augmenting the theory of planned behaviour: Motivation to provide practical assistance and emotional support to parents

Abstract

Surveys indicate that the highest proportion of people receiving informal care are parents (Green, 1988), yet a literature search showed that psychological studies of motivation to care for parents are limited. The present study utilised an augmented model of the theory of planned behaviour (Ajzen, 1985) including measures of anticipated regret and carer self-concept, to examine individuals' motivations to provide practical assistance and emotional support to their parents. Intention to provide emotional support was predicted by the theory of planned behaviour constructs, while intention to provide practical assistance was predicted by subjective norm and perceived behavioural control but not by attitude. Anticipated regret substantially improved prediction of both types of behavioural intention. These findings indicate that providing practical assistance and emotional support are motivated behaviours, governed by both rational and emotional factors, suggesting that future research may benefit from adopting a broader perspective based upon social psychological theory     

Predicting uptake of a routine cervical smear test: A comparison of the health belief model and the theory of planned behaviour

Abstract

This paper reports on a study carried out to identify predictors of uptake of cervical screening among 142 women (59% response rate) in inner London. Two social cognition models were used: The Health Belief Model (HBM; Becker, 1974) and the Theory of Planned Behaviour (TPB; Ajzen, 1991) and in addition anticipated affect following non-attendance for screening was assessed. The TPB emerged as by far the superior model for predicting screening intentions, explaining 51% of the variance in comparison with only 4% explained by the HBM variables. However, neither model was able to predict a significant amount of variance in uptake of screening three months later. Possible reasons for the poor prediction of this type of behaviour are discussed.     

Young adults' intention to eat healthy food: Extending the theory of planned behaviour

Abstract

The present study predicts adults' intention to eat healthily, using the theory of planned behaviour (TPB) and additive and moderating effects of role identity, group norms and group identification, derived from identity theory and self categorisation theory. A total of 735, 25 years old adults participated in a mailed questionnaire survey in 1997. The TPB explained 52% of the variance in young adults' decision to eat healthily, with perceived behavioural control and subjective norms being the strongest (β= .56, p < .001) and weakest (β = .05, p < .005) determinants, respectively. Although, role identity accounted for an additional amount of 4% of the variance in behavioral intention, past behaviour did not moderate the impact of role identity on intention, as hypothesised. Neither perceived group norm nor group identification added to the prediction of intention over and above the TPB. However, group identification was found to act as a moderator on the relation between group norm and behavioural intention in the predicted direction. The wider social context seems to play a stronger role for the formation of adults' healthy eating decisions than indicated by the TPB.     

A randomized controlled trial of expressive writing in breast cancer survivors with lymphedema

Objective: Breast cancer survivors who develop lymphedema report poorer quality of life (QoL) than those without lymphedema. Expressive writing is a potential intervention to address QoL.

Design: Adult women (N = 107) with breast cancer and chronic Stage II lymphedema were randomised to writing about thoughts and feelings specific to lymphedema and its treatment (intervention) or about daily activities (control) for four, 20-min sessions.

Main Outcome Measures: Outcome measures were several indicators of QoL assessed at baseline, one, three, and six months post-intervention (total scores and subscales of Upper Limb Lymphedema 27 and Functional Assessment of Cancer Therapy–Breast). Hypothesised moderators of change in QoL were dispositional optimism, avoidant behaviours, and time since lymphedema diagnosis.

Results: There was no statistically significant intent-to-treat main effects of expressive writing on QoL. Statistically significant moderating effects on change in different indicators of QoL were observed for all three moderators. Expressive writing was more effective for improving QoL in women who were higher on optimism, lower on avoidance and had less time since a lymphedema diagnosis.

Conclusion: These results provide further evidence that there are subsets of individuals for whom expressive writing is more effective. Future research may investigate targeting expressive writing based on identified moderators.     

Students' online collaborative intention for group projects: Evidence from an extended version of the theory of planned behaviour

Given the increasing use of web technology for teaching and learning, this study developed and examined an extended version of the theory of planned behaviour (TPB) model, which explained students' intention to collaborate online for their group projects. Results indicated that past experience predicted the three antecedents of intention, while past behaviour was predictive of subjective norm and perceived behavioural control. Moreover, the three antecedents (attitude towards e‐collaboration, subjective norm and perceived behavioural control) were found to significantly predict e‐collaborative intention. This study explored the use of the “remember” type of awareness (i.e. past experience) and evaluated the value of the “know” type of awareness (i.e. past behaviour) in the TPB model.     

Predictive validity of the theory of planned behaviour: the role of questionnaire format and social desirability

The present study was designed to assess the predictive validity of a theory of planned behaviour extended to include self‐identity, in the context of health‐related food choice. Following criticism of the use of questionnaires in social cognitive research, the impact of questionnaire format (random vs structured) and social desirability on questionnaire responses was assessed. Findings indicated that intention was the principal determinant of food choice; attitude, subjective norm and self‐identity were independently predictive of intention. There was only weak evidence to suggest effects of social desirability or questionnaire format on component relationships. The present study indicates that the impact of questionnaire format and social desirability on models such as the theory of planned behaviour is minimal, and that such models are robust predictors of food choice. Copyright © 1999 John Wiley & Sons, Ltd.     

Expectations of reducing fat intake: The role of perceived need within the theory of planned behaviour

Abstract

Dietary fat intake has been implicated in the causation of major diseases including coronary heart disease and cancer. Hence, current recommendatioris to improve health emphasise the reduction of fat intake (COMA, 1991). The present study investigated the effect of perceived need to reduce fat intake and past behaviour on peoples' expectations of reducing fat intake, using the framework of the Theory of Planned Behaviour (TPB) (Ajzen, 1985; 1991). The effects of estimated fat intake and body weight on perceived need to reduce were also investigated. One hundred and fifty-two adults completed a four-day weighed dietary record and completed a questionnaire based on the TPB. Perceived need to reduce fat intake, cognitive and affective components of attitude and past behaviour wm found to be significant predictors of expectation of reducing fat intake. Perceived body weight and estimated fat intake were significant predictors of perceived need to reduce fat intake. The implications of these findings for health promotion policy are discussed.     

The effect of self‐identity alongside perceived importance within the theory of planned behaviour

Self‐identity often predicts behavioural intentions after standard theory of planned behaviour (TPB) components are accounted for. However, it has been claimed this is due to conceptual similarity between self‐identity and perceived importance of the behaviour. We examined this claim within the context of recycling food waste. Participants (N = 113) completed questionnaires assessing intentions, attitude, perceived behavioural control, perceived norms, perceived importance, self‐identity, and past behaviour. Confirmatory factor analysis indicated that self‐identity and perceived importance were distinct constructs. Further, after accounting for TPB components and perceived importance, self‐identity explained a significant amount of additional variance in intentions. The present findings therefore do not support this particular argument against the predictive utility of self‐identity.     

Neuroticism,conscientiousness and fruit consumption: Exploring mediator and moderator effects in the theory of planned behaviour

Integrating the theory of planned behaviour (TPB) with the five-factor model (FFM) of personality may provide insight into the cognitive and motivational mechanisms linking personality with health behaviour, but this issue has received very little attention regarding fruit consumption. Mediator effects of TPB concepts in the personality–fruit consumption link, as well as moderator effects of personality in the intention–fruit consumption link, were therefore investigated in the present study. Data on fruit consumption, TPB concepts and FFM dimensions were gathered among 405 respondents in face-to-face interviews using questionnaires. Structural equation modelling was used to investigate the mediator and moderator effects. The direct effect of conscientiousness on fruit consumption was mediated by attitude and perceived behavioural control, while no direct effect of neuroticism on fruit consumption was found. Neuroticism moderated the intention–fruit consumption relationship with the weakest relationship for those scoring high on neuroticism. Conscientiousness did not moderate the intention–fruit consumption relationship. TPB variables are mediators in the conscientiousness–fruit consumption link. Whether fruit consumption is intentional may be dependent upon the personality dimension neuroticism. Personality dimensions may be a useful addition to the TPB and should be considered in health behaviour change interventions.     

Using the theory of planned behaviour to predict screening uptake in two contexts

Given current policy that decisions about screening should be based on informed choice, such decisions should reflect people's values and attitudes. This prospective study compares the attitudes and other cognitive predictors of screening uptake in two contexts: when conducted as part of a routine visit and when it is conducted at a separate, test-specific visit. It was conducted in two hospitals in England, differing in method of screening organisation. 1499 pregnant women offered serum screening for Down Syndrome completed a questionnaire assessing theory of planned behaviour constructs: attitude towards undergoing the test, subjective norms of others, perceived behavioural control and intention to undergo the test.

Intention predicted screening uptake in both screening settings, but more strongly when screening was part of a routine visit. Perceived behavioural control was not predictive of uptake, and only weakly predictive of intention in both settings. Subjective norm predicted intention more strongly when it referred to partner and friends than when it referred to health professionals, in both settings.

Attitude was more strongly predictive of intention to attend screening when screening was organised as a part of routine screening, rather than requiring a separate visit. These results suggest that offering a screening test at a routine visit compared with a separate visit is more likely to facilitated uninformed choices, given the stronger association between attitudes and intention and the absence of an association with the perceived influence of health professionals.     

Conceptual overlap between moral norms and anticipated regret in the prediction of intention: Implications for theory of planned behaviour research

Moral norms and anticipated regret are widely used extensions to the theory of planned behaviour, yet there is some evidence to suggest that these constructs may conceptually overlap as predictors of intention. Two health-related behaviours with distinct moral implications (Study 1: organ donation registration, N?=?352 and Study 2: condom usage, N?=?1815) were therefore examined to ascertain whether moral norms and anticipated regret are indeed conceptually distinct. While evidence consistent with conceptual overlap was identified in Study 1, the evidence for such overlap in Study 2 was more ambiguous. In Study 3, a meta-analysis of existing literature revealed that the relationship between moral norms and anticipated regret was moderated by the extent of the moral implications arising from the behaviour under examination. Taken together, these findings suggest that conceptual overlap between moral norms and anticipated regret is more likely to occur among behaviours with obvious moral implications. Researchers wishing to examine the predictive utility of moral norms and anticipated regret among such behaviours would therefore be advised to aggregate these measures to form a composite variable (personal norms).