Verification of a theory of planned behavior model of medication adherence in Korean adults: Focused on moderating effects of optimistic or present bias

Background: In order to prevent or recover from a disease, prescription must be correct, but it is also important for patients to adhere it. Therefore, this study verified a theory of planned behavior (TPB) model to predict the medication adherence of Korean adults and examined the role of optimistic bias or present bias in that model. Methods: : The participants were 357 Korean male and female adults whose ages ranged from 18 to 76 ( M =41.53, SD =9.89). Their medication adherence was measured with the Morisky Medication Adherence Scale, the TPB factors using modified items related to medication adherence, and optimistic bias using items developed, based on the concept and previous studies. Results: : An alternative TPB model, including a direct path from attitude to behavior and a direct path from the perceived behavioral control to behavior an insignificant path from behavioral intention to behavior, was validated for Korean adults’ medication adherence. This model was found to be moderated by optimistic bias or present bias. Conclusion: The findings of this study should provide useful information for future research and for medical or health professionals who wish to improve the medication adherence of their patients.