Applying the theory of planned behavior to study health decisions related to potential risks

This study examines theoretical linkages between the Risk Information Seeking and Processing model (RISP) and the Theory of Planned Behavior (TPB) in a context of health decision making related to potential risks involved in clinical trials. A decade after the RISP model was proposed, abundant empirical evidence attesting to the model's robustness in depicting individuals' motivations for risk information seeking and processing deems that it is crucial to continue this exploration. Data from two telephone surveys showed that individuals who tended to process relevant risk information in a more systematic manner were more likely to report favorable attitudes toward clinical trials and express a willingness to enroll in a future trial. Those who reported greater trust in their doctors were also more likely to report favorable attitudes and willingness to enroll. In contrast, risk perceptions were negatively related to favorable attitudes toward clinical trials. Comparing several structural models specified to the data, individuals' tendency to rely on independent decisions seemed to moderate the relationship between subjective norm and behavioral intention. Using regression coefficients estimates to plot this interaction, among those who tended to rely on independent decisions, influence from their doctors might lead to less willingness to enroll in a future trial. Results from this study suggest that in an effort to pursue theory development within a unique research context, we could also identify important pathways to improve health communication practice related to patient accrual for clinical trials.