Background: Although bivariate relationships between depressive symptoms, health beliefs, and medication adherence have been identified, the complex relationship among these 3 constructs has not been explicated.
Objective: This study examines the mediating role of patients' beliefs about diabetes and diabetes medications in relation to depressive symptoms and diabetes medication adherence.
Methods: A survey was sent to 1700 persons with type 2 diabetes who were enrolled in a managed care organization in the United States. The bivariate relationships between depressive symptoms, diabetes-related health beliefs, and diabetes medication adherence were assessed. A structural equation model was developed to determine if health beliefs mediated the relationship between depressive symptoms and medication adherence.
Results: Usable responses were received from 445 subjects. Greater depressive symptoms were associated with lower adherence to diabetes medications. The structural equation model indicated that the effect of depressive symptoms on medication adherence was mediated through perceived side effect barriers, perceived general barriers, and self-efficacy. Patients with severe depressive symptoms perceived more barriers to treatment adherence and were less confident in their ability to adhere to medication. In turn, reduced self-efficacy and heightened perceived barriers had a negative association with patients' adherence to diabetes medication regimens.
Conclusions: Decreased adherence to diabetes medications in patients with both diabetes and depressive symptoms may be partly explained by the association of depression with patients' beliefs about diabetes medications and their self-efficacy for medication use.