Personality makes a difference: attachment orientation moderates theory of planned behaviour prediction of medication adherence

Abstract

Background: Although medication has been proven effective in reducing recurrence and mortality following acute coronary syndrome (ACS), patients adhere differentially to medication recommendations. To achieve a comprehensive understanding of patients’ adherence to medication recommendations following ACS, we followed up on recent calls for integrating personality theories into health psychology research. Specifically, we assessed the possible moderating role played by attachment orientation (Attachment Theory; Bowlby, 1969) in the effects of attitudes, subjective norms and perceived behavioral control (PBC) as derived from the Theory of Planned Behavior (TPB; Ajzen, 1991), on intention and reported medication adherence. Methods. A prospective longitudinal design was employed, with two measurement time points. During hospitalization, ACS male patients (N=106) completed a set of self-report questionnaires including socio-demographic variables, attachment orientation, and measures of TPB constructs. Six months after discharge, 90 participants completed a questionnaire measuring adherence to medication recommendations. Findings. As hypothesized, attachment orientation moderated the relationship between TPB variables and intentions as well as the direct and indirect effects of PBC on adherence. Findings indicate that PBC does not predict intentions and adherence among highly anxiously-attached individuals, and that subjective norms may inhibit highly avoidant- attached patients' intentions, such that for them, subjective norms are negatively associated with intentions. Conclusions. Cognitive variables appear to explain both adherence intention and adherence behavior in accordance with people's individual personality characteristics. Integrating personality and cognitive models may prove effective in understanding patients' health behaviors.